City of Sunnyvale
TO: City Council
FROM: Mary Jeyaprakash, Project Planner
PROJECT: 800 Carlise Way Well and Water Tank Project (2022-0741) Response to Late Comments on EIR
AGENDA ITEM: 3
DATE: July 16, 2026
This supplemental staff memo addresses questions and comments on the Focused Environmental Impact Report for the project that the City received after the Planning Commission meeting on March 9, 2026.
Thi
s Memo includes project merit-related responses in Appendix A and California Environmental Quality Act (CEQA)-related responses in Appendix B.
Memo
Attachment 13
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Appendix A
Proj
ect Merit-Related Responses
The following are City responses to non-CEQA comments that relate to the merits of the proposed project.
1. Wh
at are the allowable uses by Cal Water as the site stands today and can we restrict those with the project going forward? The primary concern is that Cal Water uses the site for construction lay down which is disruptive to the surrounding community.
Response:
The site is zoned R-0 and the current zoning designation allows ‘public utility buildings and service facilities’ through a Use Permit. Cal Water currently holds active permits issued by the Department of Public Works to upgrade their water pipelines on the public right-of-way. As part of that project, Cal Water is using the site at 800 Carlisle Way for construction staging and laydown activities. These activities remain subject to the City's noise regulations. The Sunnyvale Municipal Code prohibits loading, unloading, and other noise-generating activities that could disturb nearby residents between 10:00 p.m. and 7:00 a.m. Construction activities are also limited to 7:00 a.m. to 6:00 p.m., Monday through Friday, and 8:00 a.m. to 5:00 p.m. on Saturdays. The City's Planning Division recently received complaints regarding noise associated with construction staging activities at the site and reminded Cal Water of these operational restrictions and the requirement to comply with the City's noise regulations.
2. C
an the member of the public, meet with the consultant on vibration data? Response:
The City encourages all interested residents to submit written comments, which will be forwarded to the project team, including the technical consultants. Responses to all comments will be published prior to the upcoming public hearing so that all residents, Council members, and other interested parties have equal access to both the comments and the City's responses.
In addition, the public had opportunities to participate throughout the environmental review process, including the scoping meeting, community outreach meetings hosted by Cal Water, and public hearings conducted by the City. To ensure a fair and transparent public review process, we recommend that questions and comments be submitted through the public review process rather than through individual meetings with the technical consultants. This approach ensures that all input is considered and addressed through a transparent process that is accessible to all members of the public.
3. H
ow would the proposed project benefit the Sunnyvale community? Response:
The proposed well is part of Cal Water’s district-wide potable water system serving the Los Altos Suburban District. Although it supports the broader water system, the project would directly benefit the City by enhancing the reliability of water service for approximately 2,000 service connections and 7,800 residents within the city. The additional groundwater supply would help ensure a dependable source of safe drinking water during periods of peak demand, Attachment 13
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planned or unplanned system outages, drought conditions, and other emergencies for the current and future population.
4. D
id the EIR consider the impacts on the groundwater basin and does this well pull from the same supply that Sunnyvale wells pull from?
Response:
The proposed Cal Water well would draw groundwater from the Santa Clara Subbasin, which is the same basin that Sunnyvale wells pull from. Both systems are managed by Valley Water's sustainable groundwater management program (this info is included in Sustainable Groundwater Management Technical Memorandum - Initial Study Appendix D of the Draft EIR). The EIR evaluated whether the proposed pumping would adversely affect the long-term sustainability of the shared groundwater resource and concluded that the project would not deplete groundwater levels, reduce groundwater storage capacity, cause land subsidence, or degrade groundwater quality. Additional technical studies prepared for the project, such as a hydrology and water quality studies, resulted in the same conclusion. (a) W
ould granting this Use Permit create a General Plan policy change? Response:
No, Sunnyvale Municipal Code Chapter 19.18.030 allows consideration of the use through a Use Permit. The project is consistent with several General Plan policies noted in Attachment 4 of the July 21, 2026, Report to Council, specifically related to quality supply and reliability.
5. Would the nonconforming use section below apply for the existing site? Re
sponse:
No. Sunnyvale Municipal Code Section 19.12.150 defines a nonconforming use as a use that is unlawful. Use of the site as a well can be considered through a Use Permit and is not prohibited or unlawful.
6. Wo
uld water well destruction or abandonment require a permit from Planning or Building division?
Response:
No, water well destruction or abandonment does not require a permit from the City’s Planning or Building division. A permit is required by Valley Water. Cal Water has confirmed that proper permits were previously obtained.
7. Wh
y was the discussion about alternative well sites restricted to Sunnyvale (at the Planning Commission hearing), while there must be more opportunities in the other areas so much larger than the service area in Sunnyvale.?
Response:
Cal Water already evaluated alternative sites and found that there is no other viable site for a new groundwater extraction well within the Los Altos Suburban service district. The City also Attachment 13
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does not have any similarly sized parcels of surplus land that could be used in exchange for the project site.
CEQA Guidelines Section 15126.6 (f)(3) states: An EIR need not consider an alternative whose effect cannot be reasonably ascertained and whose implementation is remote and speculative.
Therefore, an alternative site outside Sunnyvale can only be considered, when impacts of the project might be avoided or reduced, and when the City can feasibly attain control of the site and therefore the project. The City has no approval authority over sites in other jurisdictions. 8 . The image posted on the well property fence does not show that new landscaping so it is at least 13 years old?
Response:
It is the satellite image used in one of the earlier presentations and use of this image does not diminish or alter the site condition or the project.
9 . Instead of a stipend, spend the money on replacing the decrepit, ill-constructed fence. I see they put up supports for the fence. These just prop up a shoddy ill-constructed fence with rotting wood. Instead of overlapping for privacy and noise reduction, there are literally inches between the upright boards. We can see the workers through the fence. Our back windows are visible through to Carlisle at night. The wood in contact with the ground and elsewhere is deteriorating. The crosshatch panel added to the top still has weeds that were never cleaned up when they removed the ivy. It is also in poor condition. The fence should be higher with no gaps to keep out noise and, heaven forbid, fumes that occurred when Sprint put in a generator. Fo r
ad
ditional noise reduction, Cal Water should be required to build a taller fence with better quality wood that overlaps with no gaps. Also, a more knowledgeable contractor might be in order.
Response:
City records indicate that Cal Water installed replacement chain-link fence along north and west and new wooden fence along east and south in 2011. While the scope of this project does not include replacement of the fence, the City Council may decide to condition the project to replace the existing fence as part of their public deliberation. 1 0. One of the two impacted residents is in her 80s and unable to move to a hotel. How can we accommodate her mobility restrictions and still meet the project goals? Response:
A condition of approval will be added such that Cal Water will make reasonable accommodations for residents with mobility restrictions or other accessibility needs to facilitate their temporary relocation to and from the hotel, including arranging appropriat e
t
ransportation or other necessary assistance in consultation with the affected resident. 1 1. One of the residents is a suicide prevention therapist and is concerned she won’t be able to take emergency calls from clients in the middle of the night due to noise.
Response:
The applicant’s noise model estimates the mitigated noise level to be up to 57.7 decibels at adjacent residences, which is approximately equivalent to the hum of a dishwasher or refrigerator. Further, these noise levels are estimated conservatively outside at the edges of property lines, so noise levels experienced inside homes will be reduced. Based on the noise model, a significant disruption to typical indoor activities is not likely. However, in the event Attachment 13
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that a neighbor feels impacted, Cal Water is providing hotel vouchers to all adjacent neighbors as an additional mitigation measure. Use of the hotel vouchers is voluntary. The vouchers are intended to provide any affected residents with the option of staying at a hotel during drilling activities, allowing them to avoid the construction noise altogether. 12 . How does the project mitigate the impact of potential fire risk from construction? Response:
Fire prevention during construction will be addressed through Cal Water's standard construction specifications and compliance with applicable fire safety requirements. Cal Water's contractor is required to perform all work in a fire-safe manner, provide and maintain adequate on-site firefighting equipment capable of extinguishing incipient fires, and comply with all applicable federal, state, and local fire prevention regulations. Where such regulations do not apply, the contractor must follow the applicable provisions of the National Fire Protection Association's Standard for Safeguarding Construction, Alteration, and Demolition Operations (NFPA 241). These requirements are intended to minimize the potential risk of fire during construction activities.
13 . Are there people on site all night during construction to ensure security? Response:
Yes. Personnel will be present on site throughout nighttime drilling activities. In addition, Cal Water will designate a 24-hour point of contact whose contact information will be provided to neighboring residents. Neighbors may contact this representative at any time during construction to report concerns or ask questions, including those related to site operations or security.
14 . A question was submitted regarding the possibility of installing the 35-foot sound wall without removing trees. Cal Water previously stated that, “The existing trees on site would not interfere with the proposed sound barrier, which would be positioned to prevent damage to existing trees that are planned to remain”. Does the City have any measures in place for what would occur if this turns out to not be the case? Is the project required to comply with a tree protection plan during construction?
Response:
The project site includes both protected trees and trees that are below the size threshold for protection under the City's tree preservation requirements. The proposed location of the temporary 35-foot sound barrier has been designed based on the locations of the existing trees to avoid impacts to protected trees that are planned to remain. The project proposes the removal of six trees to accommodate the proposed well and water tank improvements, four of which are protected trees. The remaining protected trees are expected to be preserved and protected during construction, including during installation and removal of the temporary sound barriers. The project will be required to comply with the City's tree protection requirements, including implementation of approved tree protection measures during construction to avoid damage to retained trees, part of COA. 15 . Findings for the Use Permit ask for ‘the use to not impair adjacent properties.’ With the overriding consideration asking for substantial impact after mitigation, there is going to be obvious disruption to the community. How can the project meet this finding for UP? Attachment 13
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Re
sponse:
The required findings for the Use Permit and the CEQA findings address different legal standards and evaluate different types of impacts. The Use Permit finding regarding impairment of adjacent properties considers whether the proposed use, by its nature and operation, would be compatible with surrounding properties from a land use and planning perspective. In contrast, the Statement of Overriding Considerations under CEQA acknowledges that, despite implementation of all feasible mitigation measures, the project would result in a significant and unavoidable environmental impact related to nighttime construction noise. These findings are not inconsistent because they serve different purposes under separate regulatory frameworks and therefore cannot be directly compared.
16 . One hotel room is not enough for a family of four.
Response:
Recommended condition of approval GC-7.b. was prepared to account for additional rooms needed per family:
17 . Request Calwater to take out $500,000 bond for each adjacent property to cover potential damage.
Response:
Applicants are required to obtain liability insurance as part of their building permit issuance to cover potential damage to neighboring properties during construction.
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Appendix B
CEQA-Related Responses
In accordance with the California Environmental Quality Act (CEQA) and the CEQA Guidelines (Public Resources Code Section 21092.5[a] and CEQA Guidelines Section 15088[b]), the City of Sunnyvale prepared a Final Environmental Impact Report (EIR) that included written responses to significant environmental issues raised in comments received on the Draft EIR during its public circulation period (May 15, 2025 to June 30, 2025). The Final EIR and all documents referenced in the Final EIR were published and made available for review to agencies and the public (including individuals who provided comments on the Draft EIR) on February 6, 2026.
S
ubsequent to the publication of the Final EIR and as of March 5, 2026, three written comment letters were submitted to the City on the EIR. These comments were responded to in the 800 Carlisle Way Well and Water Tank Project (2022-0741) Response to Late Comments on EIR Memo dated March 9, 2026 prepared by City staff (hereinafter also referred to as the “March 9, 2026 staff memo”). This staff memo was published and included as Attachment 12 to the staff report for the March 9, 2026 Planning Commission hearing. Since the Planning Commission hearing that was held on March 9, 2026, and as of July 16, 2026, several comment letters were submitted to the City on the project and EIR. Copies of these letters are provided at the end of this memorandum. The purpose of this memorandum is to provide written responses to the late comments related to the adequacy of the CEQA document in these recent letters for consideration by the City Council prior to the public hearing to consider the certification of the Final EIR. Comments regarding the merits of the project or other items not pertaining to significant environmental issues (e.g., permitting history, zoning interpretations, nonconforming uses, required permit findings, statement of overriding considerations) are being addressed separately by City staff (see Part 2). No comments in the letter dated May 6, 2026 are relevant to the adequacy of the CEQA document; therefore, none are included or responded to below.
C
omments were received expressing concern that the responses to comments in the March 9, 2026 staff memo were not included in the Final EIR. However, those responses could not have been included in the Final EIR as the Final EIR had already been published before the comments addressed in the March 9, 2026 staff memo were received. The City Council relies upon and considers the entirety of the administrative record when considering approving a project. What constitutes the administrative record (also referred to as the “record of proceedings”) is described in Public Resources Code Section 21167.6(e) and includes the EIR (including the Draft and Final), all staff reports, and all public and agency comments.
C
EQA Guidelines Section 15088.5 states that a lead agency is required to recirculate an EIR when significant new information is added to the EIR after public notice is given of the availability of the Draft EIR for public review, but before the Draft EIR is certified. CEQA Guidelines Section 15088.5 Attachment 13
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clarifies that new information added to an EIR is not “significant” unless the EIR is changed in a way that deprives the public of a meaningful opportunity to comment upon a substantial adverse environmental effect of the project or a feasible way to mitigate or avoid such an effect (including a feasible project alternative) that the project’s proponents have declined to implement. The following examples would qualify as significant new information that could require recirculation of the Draft EIR:
1. A
new significant environmental impact would result from the project or from a new mitigation measure proposed to be implemented.
2. A substantial increase in the severity of an environmental impact would result unless mitigation measures are adopted that reduce the impact to a level of insignificance.
3. A feasible project alternative or mitigation measure considerably different from others previously analyzed would clearly lessen the environmental impacts of the project, but the project’s proponents decline to adopt it.
4. The draft EIR was so fundamentally and basically inadequate and conclusory in nature that meaningful public review and comment were precluded.
No
ne of the comments received subsequent to the publication of the Final EIR or the responses to those comments are considered significant new information warranting text revisions to the Draft EIR.
Th
e EIR includes substantial evidence (e.g., facts, reasonable assumptions predicated upon facts, and expert opinion supported by facts) to support the conclusions in the EIR. Argument, speculation, unsubstantiated opinion or narrative, evidence which is clearly erroneous or inaccurate, or evidence of social or economic impacts which do not contribute to or are not caused by physical impacts on the environment do not constitute substantial evidence (CEQA Guidelines Section 15384). In addition, the standard of review for an EIR under CEQA is not whether a fair argument can be made that the project has a significant effect on the environment based on alternative methods or thresholds, it is whether there is substantial evidence in the record to support the conclusions in the EIR (even though other conclusions might also be reached).
Summary of Written Comments and Responses
Based on a careful review of the comments, the City determined they raised similar, overlapping concerns and questions on the environmental effects of the project within the same topic areas.
Therefore, for clarity, readability, and to avoid potential confusion and redundancy associated with numerous responses to individual comments raising the same issue, responses for primary topic areas have been prepared. A summary of the written comments and responses to those comments are organized below by topic as follows:
I. Air Quality .................................................................................................................................... 10 II. Biological Resources ..................................................................................................................... 1 0 Attachment 13
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III. Project Description ....................................................................................................................... 1 1 IV. Water Supply Impacts .................................................................................................................. 1 2 V. Project Objectives and Alternatives Analysis ............................................................................... 1 6 VI. Off-Site Alternatives Analysis ....................................................................................................... 21 VII. Vibration Modeling ...................................................................................................................... 2 3 VIII. Noise Modeling ............................................................................................................................ 26 IX. Mitigation Monitoring and Reporting Program (MMRP) ............................................................. 2 8 X. 2016 Well Destruction ................................................................................................................. 2 9 XI. Mitigation measures for construction noise ................................................................................ 3 0 XII. Depth of the Destroyed Well ....................................................................................................... 3 3 XIII. Miscellaneous Items..................................................................................................................... 3 4 Attachment 13
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I. Air Quality
Comments received pertaining to air quality impacts included:
• A
lack of analysis regarding operational emissions of the generator • Emissions associated with operation of the generator
• Potential electric alternatives to a diesel-powered emergency generator A
n Initial Study was completed for the project and determined that impacts to most environmental resources (including air quality) would be less than significant and that an EIR primarily focused on noise should be prepared. The air quality impact discussion for the project was included on pages 35 to 45 of the Initial Study (which is included as Draft EIR Appendix A). The air quality analysis was based on a project-specific Health Risk & Greenhouse Gas Assessment (Initial Study Appendix A) prepared by the City’s technical expert.
O
perational emissions for the project associated with vehicles driven by future employees and testing of the emergency generator on-site were modeled in the technical Health Risk & Greenhouse Gas Assessment (Initial Study Appendix A) prepared pursuant to the 2022 Bay Area Air District CEQA Guidelines. As documented in technical Health Risk & Greenhouse Gas Assessment and summarized in the Initial Study (Draft EIR Appendix A), operational criteria pollutant emissions associated with the project were well below the significance thresholds established by the Air District. In addition, the project’s operation-related increased cancer risk, annual PM
2.5 concentration, and Hazard Index at the maximally-exposed individual (MEI) do not exceed the Air District single-source thresholds. Therefore, no mitigation measures were necessary to address potential air quality impacts generated by the proposed emergency generator.
A
comment was received questioning whether an electric emergency generator could replace the currently proposed diesel-powered emergency generator that would be installed on-site. Based on the electrical load required to power the equipment on-site (e.g., pumps, valves, control systems) during an emergency situation, an electric emergency generator would not be feasible as it has a finite energy storage capacity that would quickly be depleted. Conversely, the proposed diesel- powered emergency generator would be able to effectively manage the required electrical load, and staff would be able to refuel the generator, as needed, during an emergency situation.
II. Biological Resources
Comments received regarding biological resources pertained to:
• I
nconsistency in proposed tree removal numbers
• Feasibility of the proposed mitigation measures without addition tree removal Attachment 13
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The project site includes both protected trees and trees that are below the size threshold for protection under the City’s tree preservation requirements. The Final EIR disclosed that the proposed project would remove nine total trees. Subsequent to the publication of the Final EIR, in June 2026, the applicant clarified that the proposed project would remove a total of ten trees, including seven protected trees and three unprotected trees. Four of the trees proposed for removal are either diseased, dead, or dying. The other six trees would be removed to construct the new well and storage tank (i.e., their removal is required to accommodate the proposed well and water tank improvements). An Errata dated June 17, 2026, was prepared by the City to clarify this minor change and document that this clarification would not alter the analysis or conclusions of the EIR.
With the removal of the ten existing trees, 28 existing trees would remain on-site (eight protected trees and 20 unprotected trees). The proposed location of the temporary 35-foot sound barrier required by mitigation measure MM NOI-1.1 has been designed to avoid impacts to the existing protected trees that are planned to remain. As discussed on page 51 of the Initial Study (Draft EIR Appendix A), the remaining protected trees would be preserved and protected during construction, including during installation and removal of the temporary sound barriers, pursuant to Sunnyvale Municipal Code Chapters 13.16 and 19.94. The project would be required to comply with the City’s tree protection requirements, including implementation of approved tree protection measures during construction to avoid damage to retained trees.
III. Project Description
Comments received regarding biological resources pertained to:
• Consistency in the project description regarding the status of the previous water well that operated on-site
• Difference in terminology (e.g., destroyed, capped, reactivate)
Comments were received regarding perceived inconsistencies within the Draft EIR’s description of the status of the former groundwater well on-site. Relevant portions of text noted within Section
2.2 of the Draft EIR are listed below, including underlined text additions from the Final EIR.
• The project site was formerly used as a groundwater extraction site for California Water Service (Cal Water) to provide potable water to their Los Altos Suburban service district. • The site consisted of a water well and associated chemical storage buildings, a cellular communication tower, booster pump, and a 17-foot tall, 50,000-gallon water storage tank (through Planning Permits - #1999-0687 and #2001-0319). In 2016, the water well on-site was decommissioned and properly destroyed due to sanding issues and casing deterioration within the well.
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• To provide water supply reliability and meet current customer water supply demands, Cal Water is proposing to reactivate the site as a groundwater extraction site by constructing a replacement well and associated improvements to accommodate current and future water demands.
• The previous groundwater well that was capped in 2016 is located in the center of the site on the north side. The new well would be located on the southwest portion of the site and would reach a depth of approximately 1,000 feet below ground surface (bgs).
Wh
ether the EIR describes the previous groundwater well on-site as being decommissioned, destroyed, or capped, the language in the EIR is consistent in referring to the previous groundwater well on-site as no longer being in operation. The EIR is also consistent in describing the proposed groundwater well as a replacement groundwater well, which qualifies as new construction. The word “reactivate” is used in a single sentence in the project description to describe the project site itself as being reactivated as a groundwater extraction site through construction of a replacement well (refer to the third bullet above). No mention of the destroyed groundwater well being reactivated is included in the EIR. A comment notes that “capping” a well can be a temporary or reversible measure for a groundwater well. In general, groundwater wells can be temporarily capped or permanently capped. However, the language in the Draft and Final EIR is clear that the proposed project is a new groundwater well separate from the former well that was operational on- site. The former well shall remain unused.
IV. Water Supply Impacts
Comments received pertaining to potential water supply impacts included:
• Wh
ether the project provides benefit to the City
• Whether impacts to the groundwater basin were considered • Whether this well would draw water from the same supply that the City of Sunnyvale uses for their groundwater wells
S
everal comments were received regarding the project not providing a direct benefit to adjacent residences or the City, as Cal Water (the applicant) does not provide water to the adjacent residences. As noted on page 8 of the Draft EIR:
The project site was formerly used as a groundwater extraction site for California Water Service (Cal Water) to provide potable water to their Los Altos Suburban service district. This service district encompasses the City of Los Altos and portions of Cupertino, Los Altos Hills, Mountain View, Sunnyvale and adjacent unincorporated areas of Santa Clara County. The service district delivers potable water to approximately 18,000 service connections (approximately 2,000 of which are located in Sunnyvale) and a population of approximately 70,000 customers.
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Therefore, while the adjacent residences to the east and south of the project site may not receive a direct benefit from the water pumped from the proposed groundwater well on-site, this additional water source would be used to serve approximately 2,000 service connections within the City (approximately 7800 Sunnyvale residents), including residents near the project site north of Carlisle Way and east of Wolfe Road.
T
he City of Sunnyvale water supply is primarily obtained through purchased water from the San Francisco Public Utilities Commission (SFPUC) and Santa Clara Valley Water District (Valley Water).
This is supplemented with local groundwater wells. In the northern part of the City, recycled water is used for non-potable uses, comprising of approximately 0.5 percent of the supply.1 In addition, the City has multiple potable water interties with Cal Water (the applicant) and the cities of Santa Clara, Mountain View, and Cupertino, which could provide water service in the event of an emergency.
2 F
igure 3-1 from the City’s adopted Urban Water Management Plan has been excerpted and provided on the following page. The figure shows which entity provides water to different areas of the City. Customers within the City receiving water from Cal Water are shown in red on the figure and include residents on the north side of Carlisle Way.
T
he project’s potential impacts to the Santa Clara Subbasin were evaluated under the applicable impact discussions on pages 72 to 73 and 98 to 101 of the Initial Study (which is included as Draft EIR Appendix A). As discussed on page 99 of the Initial Study:
According to Valley Water, “the Santa Clara Subbasin is not in a condition of chronic overdraft due to the managed recharge of local imported water as well as in-lieu recharge activities.” Between 2010 and 2019, the water budget for the Santa Clara Plain principal aquifer showed an average inflow of 86,000 AFY and an average outflow of 83,000 AFY, which resulted in an average annual increase in storage of approximately 3,000 AFY in the aquifer.
I
n 2023, approximately 112,200 AF of groundwater was pumped from the Santa Clara Subbasin. As discussed under Impact GEO-3, the maximum annual production of the proposed well would be approximately 1,935 AF of groundwater per year, which would account for approximately 1.7 percent of the total annual amount pumped from the Santa Clara Subbasin. Cal Water is permitted to pump groundwater from the Subbasin, and although the project would result in a nominal increase in groundwater pumped from the Santa Clara Subbasin, the 1,935 additional AFY would not result in a significant increase in groundwater outflow and Valley Water would be able to continue to manage groundwater to sustainable levels.
T
herefore, the additional amount of groundwater extracted from the Santa Clara Subbasin by the project would not impact the long-term sustainability of the groundwater supply in the subbasin and would not affect the City’s ability to extract groundwater from the subbasin through the 1 City of Sunnyvale. 2025 Urban Water Management Plan. Adopted June 16, 2026. Table 6 -8: 2025 Water Supplies – Actual (AFY). Page 55.
2 City of Sunnyvale. 2025 Urban Water Management Plan. Adopted June 16, 2026. Page 24.
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groundwater wells that they own and operate. In addition, Valley Water, who is responsible for managing the sustainability of groundwater levels in the Santa Clara Subbasin, reviewed the project and Draft EIR and did not have any comments regarding the amount of water that would be extracted by the proposed groundwater well.
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S
ource: City of Sunnyvale. 2025 Urban Water Management Plan. Adopted June 16, 2026. Figure 3-1,
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V. Project Objectives and Alternatives Analysis
Comments received pertaining to the project objectives and alternatives analysis included:
• The project objectives stating that constructing a well on-site is preferable • The alternatives being designed to evaluate alternatives to reactivation of the site instead of new construction
• The project objectives being designed to require this specific parcel • The lack of analysis regarding the potential to expand pumping capacity at other facilities or other alternatives to drilling a new water well
• Circular nature of dismissing the “No Project” alternatives • Assumed interruptions in service necessitating an incomplete review of alternatives • The viability of quieter equipment or alternative methodology for drilling activities
The project objectives are provided in Section 2.3 and 7.12 of the Draft EIR and shown in bold text.
The four objectives are:
1. Replace a critical Cal Water supply well that was previously destroyed on-site due to its age.
2. Upgrade Cal Water’s aged infrastructure in the Los Altos Suburban service district with a new well and water tank to maximize and improve the reliability of the water supply in the area.
3. Address potential drought emergency in the County of Santa Clara by generating an additional source of groundwater.
4. Address fire risk in the area generating an additional source of groundwater in the area that can be used in emergency scenarios.
Additional context for the first two objectives was provided in the Draft EIR in plain text following the objective. For Project Objective 1, the following context was provided:
Acquiring new property in the Los Altos Suburban service district (within the cities of Sunnyvale and Los Altos) is difficult, therefore, constructing the replacement well on a property that Cal Water already owns is preferable. In addition, the former well on-site produced good yields and the site is already connected to Cal Water’s existing distribution system infrastructure. Therefore, drilling and installing a replacement well on-site is an expeditious and cost-effective solution to adding additional water supply to the Los Altos Suburban service district.
A comment was submitted that states that the contextual explanation under Project Objective 1 (excerpted above) was included to require this specific parcel and preclude consideration of any off- site alternative. In addition, a comment was received stating that the Draft EIR converted the applicant’s site preference into a finding that no viable alternatives exist. The contextual text excerpted above was included to explain the rationale for proposing a new groundwater well on- Attachment 13
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site, not to preemptively dismiss consideration of any alternative site. The basic project objective is to replace a Cal Water supply well that was previously destroyed on-site – the alternatives analysis did not interpret this objective to mean the replacement well must be on-site. The Draft EIR acknowledged that Cal Water (the applicant) does not currently have any alternative off-site properties that are feasible and viable for a new groundwater extraction well within the Los Altos Suburban service district, and the City does not have any similarly sized parcels of surplus land that could be used in exchange for the project site. This was expanded upon in the City’s March 9, 2026 staff memo. The staff memo included a list of the specific sites owned by the applicant within the City and explanation of why those sites were not viable alternative sites for the project. In addition, the potential “Indirect Impacts” associated with a property acquisition by the applicant were included in the Draft EIR. The detailed evaluation of the environmental impacts associated with developing the project at an alternative site could not be included in the Draft EIR as it is speculative and CEQA does not permit speculative analyses (CEQA Guidelines Section 15126.6(f)(2(3)). The lack of available alternative sites and the indirect impacts associated with constructing the proposed project at another location within the district were discussed in detail for the selected alternatives and used to compare the potential differences in environmental impacts from the proposed project, not the applicant’s preference to utilize the proposed site for the project, as the commenter suggests.
A
s noted above in Section III Project Description, the language in the Draft EIR is consistent in referring to the previous groundwater well on-site as no longer being operational. It is also consistent in describing the proposed groundwater well as a replacement groundwater well which qualifies as new construction. The word “reactivate” is used in a single sentence in the project description to describe the project site itself as being reactivated as a groundwater extraction site through construction of a replacement well. Similarly, the project alternatives in the Draft EIR were designed to evaluate potential alternatives to the proposed project (i.e., construction of a new replacement groundwater well), not reactivation of the former well that has been destroyed and is no longer operational. These alternatives included discussion regarding the potential to construct infrastructure improvements to increase yields at other existing wells in the district (page 42 of the Draft EIR). Other alternatives suggested by a commenter (i.e., demand-side measures or interconnecting infrastructure with other water providers) cannot be feasibly enforced by the City; therefore, were not considered in the Draft EIR.
A
comment was submitted which states that the two “No Project” alternatives were rejected despite being the environmentally superior alternatives because the project objectives were written to require the site as the only feasible option. As stated above, the basic project objective is to replace a Cal Water supply well that was previously destroyed on-site. The previous well on-site was located in and provided water to the Cal Water Los Altos Suburban service district. Both of the “No Project” alternatives were rejected because they would not construct a groundwater supply well within the Los Altos Suburban service district, which is the basic objective of the proposed project.
The intent of the project is not to maintain existing conditions at the site or to redevelop the site with residential uses, which would be the respective outcomes of the No Project/No Redevelopment Alternative and the No Project/Redevelopment Alternative. In addition, the Attachment 13
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summary discussion on page 49 of the Draft EIR notes that both of these alternatives could result in indirect impacts of the same magnitude as the proposed project to other residential neighborhoods within the Los Altos Suburban service district because Cal Water would still need to secure a supplementary groundwater source to meet water demand and most of Cal Water’s existing well facilities are located within residential neighborhoods. These high-level, indirect impacts were discussed in the Draft EIR, and the specific alternative sites that the applicant has at their disposal were discussed in detail in the City’s March 9, 2026 staff memo. Although these sites were not listed specifically in the Draft EIR, the evaluation of their feasibility to serve as alternative sites for the proposed project is contained in the administrative record (as permitted pursuant to CEQA Guidelines Section 15126.6(c)) and has been made available to members of the public and decision- makers at the City.
I
n addition to the text excerpted above, the following text was also included in the Draft EIR to provide context for Project Objective 1.
Santa Clara Valley Water District (Valley Water) is planning a 10-year Pipeline Inspection and Rehabilitation project that will take significant portions of its supply system down over a phased period.
These planned shutdowns started in 2021 and are expected to extend until 2028. During the Valley Water project, Cal Water expects interruptions to the supply system between 2023 to 2026. These interruptions in supply would remove the emergency supply for Cal Water, and would increase the risk of supply shortfalls if an emergency or a break in a mainline were to occur.
A
comment was received that stated this text was used to dismiss potential off-site alternatives because there was a need to complete the EIR process quickly. As stated above, the details under the first two project objectives were included to provide context to the objectives, not to preclude consideration of other potential alternatives. The basic project objective is to replace a Cal Water supply well that was previously destroyed on-site. The Draft EIR provided a high-level discussion to acknowledge that no Cal Water or surplus City parcels were available as alternatives and then expanded upon that discussion in the City’s March 9, 2026 staff memo. The potential “Indirect Impacts” associated with a property acquisition by the applicant were included in the Draft EIR.
These “Indirect Impacts” were discussed in detail for the selected alternatives and used to compare the potential differences in environmental impacts from the proposed project. The Draft EIR alternatives analysis does not utilize, rely upon, or account for the potential interruptions in service as factor in the alternatives analysis, as the commenter suggests.
S
ince the Draft EIR was prepared, some of the maintenance work described for context under Project Objective 1 has already been completed. Valley Water completed the first of two phases of their West Pipeline project between November 2025 and April 2026. A third phase is currently scheduled to begin in November 2026 and would run through April 2027. This work is still expected to cause ongoing service interruptions for Cal Water. References in a comment letter were included regarding the potential need for subsequent environmental review pursuant to CEQA Guidelines Section 15162 due to the potential changes in the description of Valley Water’s ongoing maintenance work. The commenter is correct that CEQA Guidelines Section 15162 includes the following text:
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(a) When an EIR has been certified or a negative declaration adopted for a project, no subsequent EIR shall be prepared for that project unless the lead agency determines, on the basis of substantial evidence in the light of the whole record, one or more of the following:
(1
) Substantial changes are proposed in the project which will require major revisions of the previous EIR or negative declaration due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects; (2) Substantial changes occur with respect to the circumstances under which the project is undertaken which will require major revisions of the previous EIR or Negative Declaration due to the involvement of new significant environmental effects or a substantia l increase in the severity of previously identified significant effects; or (3) New information of substantial importance, which was not known and could not have bee n
k
nown with the exercise of reasonable diligence at the time the previous EIR was certified as complete or the Negative Declaration was adopted, shows any of the followin g:
(A) The project will have one or more significant effects not discussed in the previous EIR or negative declaration;
(B) Significant effects previously examined will be substantially more severe than shown in the previous EIR;
(C) Mitigation measures or alternatives previously found not to be feasible would in fact b e
f
easible, and would substantially reduce one or more significant effects of the project, but the project proponents decline to adopt the mitigation measure or alternat ive; or (D) Mitigation measures or alternatives which are considerably different from those analyzed in the previous EIR would substantially reduce one or more significant effects on the environment, but the project proponents decline to adopt the mitigation measure o r alternative.
A
lthough the timing of the anticipated supply interruptions has changed slightly compared to what was detailed in the Draft EIR, ongoing supply interruptions are still anticipated through at least 2027. In addition, the precise timing of these interruptions had no effect on the impact analysis in the Draft EIR or the alternatives that were considered in the Draft EIR, as noted above. Therefore, the minor timing clarifications that could be made to the description of the anticipated supply interruptions would not necessitate supplemental environmental review, as the revisions to the text would not:
• Re
sult in new significant environmental effects,
• Result in a substantial increase in the severity of previously identified significant effects, • Result in a finding that any mitigation measures or alternatives previously found not to be feasible would in fact be feasible but the project proponent declines to adopt, or • Result in a finding that mitigation measures or alternatives which are considerably different from those analyzed in the previous EIR would substantially reduce one or more significant effects on the environment but the project proponent declines to adopt.
S
ince the minor timing clarifications that could be made to the description of the anticipated supply interruptions would not meet any of the above criteria, the clarifications can be made in this memorandum as part of the administrative record for the project.
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A
comment was received stating the Draft EIR did not evaluate a mitigation measure or potential alternative equipment types or drilling methods that could produce less noise than the equipment assumed in the modeling for the proposed project. Page 39 of the Draft EIR included a discussion regarding an alternative that was considered but rejected (Alternative Equipment Type or Drilling Method):
The first alternative that was considered but subsequently rejected, was one that would utilize alternative construction equipment types that could potentially generate less construction noise during the continuous drilling activities on-site. This potential alternative was rejected from further analysis as there were no known alternative equipment types (e.g., electric, lower horsepower, etc.) or equipment that would be capable of being used for the proposed drilling and construction activities. The project would utilize the reverse rotary drilling method during the well drilling process. According to Cal Water, who has expertise in drilling and installing water wells, the machinery required for this drilling method is standard and quieter models using alternative fuels or lower horsepower are not available. Other drilling methods such as the air rotary, cable tool, bucket auger, downhole, mud rotary, and direct rotary drilling methods are not to be as effective or efficient as the reverse rotary drilling method. Therefore, there are no alternative drilling methods suitable for the proposed project that would reduce noise or time required to reach the target depth, and this alternative was not considered feasible.
A
s shown above, other methods of drilling were considered for the project. The reverse rotary well drilling method proposed for the project was selected because it is not limited by pump capacities to push fluid down during drilling, which makes it well suited for drilling large diameter groundwater wells that can reach deep aquifers. The reverse rotary well drilling method relies on the hydrostatic pressure of the fluid column pressing against the borehole wall, instead of heavy drilling mud like other drilling methods, which provides superior borehole stability during the drilling process. This reduces the risk of borehole collapse during drilling activities, reduces well wall erosion, and limits the infiltration of drilling fluids into the surrounding aquifer. In addition, the reverse rotary method offers faster penetration rates, which limits the amount of time required to drill to the proposed well depths. For these reasons, other alternative methods were determined to be infeasible for the project.
A
commenter suggested that there are other quieter drilling technologies that have been used for comparable projects; however, no specifics are provided. The comment included a statement regarding other “CEQA-governed geothermal projects in California” that identified quieter drilling technologies as mitigation, however, no substantial evidence was provided to document that these unnamed geothermal projects required similar construction objectives and methodologies (e.g., drilling depths, widths, etc.) and occur under similar conditions as the proposed groundwater well at the project site. Therefore, no substantial evidence of any quieter, equally effective drilling equipment types than those assumed for the project and evaluated in the Draft EIR has been provided. Argument, speculation, and unsubstantiated opinion or narrative that equally effective, quieter, alternative construction equipment exists do not constitute substantial evidence under CEQA.
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Although electric-powered drill rigs do exist, they would not be a practical or feasible option for construction of a deep, large diameter municipal supply groundwater well such as the proposed well. To drill a well with the depth and diameter proposed by the project, a drill rig with high torque, sustained rotary power, and substantial hoisting capacity is required. To get that functionality from an electric-powered drill rig on-site, a large diesel-powered generator would be required to provide the necessary electric power to the drill rig. As such, any potential air quality or noise benefits from utilizing an electric-powered drill rig for the project would be offset by the need to run a large diesel-powered generator during drilling activities.
VI. Off-Site Alternatives Analysis
Comments received pertaining to the off-site alternatives analysis included:
• U
navailability of surplus land
• Responses provided in the March 9, 2026 staff memo instead of the EIR • Consideration of only location alternatives within the City of Sunnyvale • Property at 781 South Wolfe Road as a location alternative T
he Final EIR included responses to comments received during the public circulation period for the Draft EIR. The Final EIR was published on February 6, 2026. Subsequent to the publication of the Final EIR, additional public comments were received on the Draft EIR. Responses to those additional comments (some of which were similar to the comments responded to in this memorandum) could not be included in the Final EIR, as the Final EIR was already published. As discussed in the introduction of this memorandum, none of the comments received subsequent to the publication of the Final EIR or the responses to those comments are significant new information warranting text revisions to the Draft EIR. In addition, the City Council relies upon and considers the entirety of the administrative record (including all staff reports and public comments and responses) when considering approving a project.
A
n alternative location is not required under CEQA. As explained on page 40 of the Draft EIR and in the March 9, 2026 staff memo, an alternative site may be considered when impacts of the project might be avoided or substantially lessened, and the project proponent can feasibly attain control of the site. Per Section 15126.6(f) of the CEQA Guidelines, factors that may be taken into account when addressing the feasibility of alternatives are site suitability, economic viability, availability of infrastructure, and whether the proponent can reasonably acquire, control or otherwise have access to the alternative site.
P
otential alternative locations (i.e., property owned by Cal Water/the applicant or the City) were considered in the Draft EIR and determined to be infeasible. Comments on the location alternative analysis were received subsequent to the publication of the Final EIR. In response, the March 9, 2026 staff memo includes clarifying details about the alternative locations considered (which included six properties owned by Cal Water within the City of Sunnyvale) and why they were found Attachment 13
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infeasible. Pursuant to CEQA Guidelines Section 15126.6(c), “Additional information explaining the choice of alternatives may be included in the administrative record.” As discussed in the introduction of this memorandum, none of the comments received subsequent to the publication of the Final EIR (or the responses to those comments) are significant new information warranting text revisions to the Draft EIR. Therefore, the standard for recirculation of the EIR has not been met.
In addition, the City Council relies upon and considers the entirety of the administrative record (including all staff reports and public comments and responses) when considering approving a project.
Per CEQA Guidelines Section 15126.6(f)(2)(3), an EIR need not consider an alternative whose effect cannot be reasonably ascertained and whose implementation is remote and speculative. CEQA does not permit speculation or conjecture, and it is speculative to assume the applicant can acquire and develop properties elsewhere that they cannot reasonably acquire, control, or have access to. As concluded in the EIR and further explained in the March 9, 2026 staff memo, the applicant does not have reasonable control or access to an alternative site for the project in the City.
The comment claiming the applicant had previously owned the property at 781 South Wolfe Road and that this property was previously used as a groundwater well site is incorrect. Based on review of government records and databases, aerial photographs, topographical maps, and interviews, as documented in the adopted Initial Study/Negative Declaration (SCH# 2025041162) that was recently prepared for the property at 781 South Wolfe Road by the City, the property was historically used for agricultural purposes until it was developed with the existing residence in 1965.
The property was not owned by the applicant and has not “housed a decommissioned well, booster pump, and chemical storage buildings” as claimed by a commenter. The 781 South Wolfe Road property is not a feasible alternative location for the project and, therefore, was not evaluated as such in the EIR because: a) the applicant does not own (nor has it owned) the property at 781 South Wolfe Road, b) the applicant cannot reasonably acquire and development this property, c) the viability of the property for groundwater extraction is speculative, and d) the recent land use approvals for the redevelopment of the property with residential uses. In fact, there is a pending Planning application (PLNG-2025-0592) to redevelop the property at 781 South Wolfe Road into single-family homes.
The applicant (nor the City who has jurisdictional authority) cannot require a private landowner in the City to sell their property to the applicant. The City, however, owns property and, therefore, it is reasonable for the City to explore whether it has any available City-owned property that could be an alternative location for the project. Since none exists, the feasibility of the applicant acquiring the City-owned property (such as compliance with the Surplus Land Act) was not discussed in the EIR.
Location alternatives outside of the City’s jurisdictional boundaries were not evaluated as they are infeasible. Pursuant to CEQA Guidelines Section 15126.6(f)(1), “regulatory limitations” and “jurisdictional boundaries” are primary factors for assessing an alternative’s feasibility. The City of Sunnyvale lacks the legal authority to approve and permit the project outside of the City’s Attachment 13
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boundaries. In addition, as discussed above, CEQA does not permit speculation or conjecture, and it is speculative to assume the applicant can acquire a site outside the City’s boundaries and that it can be approved for the project.
VII. Vibration Modeling
Comments received pertaining to the vibration modeling included:
• T
he appropriateness of the selected vibration impact threshold • Particular vulnerabilities of the surrounding residences and their foundations/glass panels • The lack of discussion regarding the effects of continuous drilling • The 17-foot measurement reference for maximum vibration levels • The accuracy of estimated vibration levels given the 17-foot reference point • The age of the reference data used for modeling vibration from construction equipment • The proprietary nature of vibration reference data
P
otential vibration impacts associated with the project were evaluated on pages 31 and 32 of the Draft EIR. A more detailed technical analysis regarding estimated vibration generated by construction of the project was included in Draft EIR Appendix B (Noise Assessment and Peer Review). The threshold utilized to determine whether the project would generate significant vibration levels that could damage surrounding structures is outlined on page 19 of the Draft EIR.
For reference, a threshold of 0.3 inches per second (ips) is typically utilized to avoid damage to older residential structures (such as the adjacent residences to the project site). However, as explained on page 19 of the Draft EIR, the City utilized a more conservative threshold of 0.25 ips (which is used to avoid damage to historic and sensitive buildings). In addition, for the purposes of this EIR, the City identified an even more restrictive significance threshold (0.04 ips) for construction activities that occur during nighttime outside of standard construction hours based on the perceptibility of vibration levels, as 0.4 ips is considered to be a perceptible level of vibration.
T
able 3-1 in Draft EIR Appendix B (Noise Assessment and Peer Review) provides a range of potential vibration thresholds for structural damage that could have been utilized for the project and is excerpted below for reference.
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As described above, the Draft EIR utilized a threshold of 0.25 ips, which is the vibration criteria for continuous/frequent intermittent sources of vibration at historic/old buildings. This threshold was deemed appropriate for the surrounding residences by the technical consultant who prepared Noise Assessment and the City’s technical consultant who completed the peer review of the Noise Assessment. In addition, the Federal Transit Administration establishes similar vibration criteria for non-engineered timber and masonry buildings (0.2 ips) and for engineered concrete and masonry buildings with no plaster (0.3 ips); both of which could have been appropriate to utilize for evaluating impacts to the surrounding residences. For these reasons, the threshold of 0.25 ips used for the EIR analysis is appropriate.
A comment was received regarding the lack of analysis about whether the continuous drilling proposed for the site would affect the conclusions of the modeling since the vibration assessment evaluates “typical” vibration levels. As noted above, a threshold of 0.25 ips, which is the vibration criteria for continuous/frequent intermittent sources of vibration at historic/old buildings, was used for the project. By comparing estimated vibration levels to the continuous threshold, the analysis evaluates the potential risk to surrounding receptors from continuous vibration during the drilling and construction phase of the project. As discussed further below, the modeled vibration levels at adjacent property lines were well below the established threshold of 0.25 ips.
As discussed on pages 31 and 32 of the Draft EIR and shown in Tables 3.1-7 and 3.1-8 of the Draft EIR, maximum vibration levels at the nearest receptor were measured to be 0.03 ips during drilling activities and 0.03 ips or lower during the remaining construction activities on-site (including demolition, site preparation, minor grading, construction, and paving). Therefore, the project would result in vibration levels below the thresholds of 0.25 and 0.04 ips and impacts during construction would be less than significant. Therefore, additional measures such as ongoing vibration level monitoring and pre-/post-construction surveys of surrounding residences cannot be required under CEQA as no significant impact was identified that warranted the imposition of mitigation measures.
However, as requested by the City of Sunnyvale Planning Commission, the applicant has prepared a Monitoring Plan that includes noise and vibration monitoring, along with a public reporting program that would be implemented throughout the drilling activities on-site. The public reporting program would provide transparent information to the City and neighboring residents daily and identify any exceedances of applicable noise or vibration thresholds, describe the source of the exceedances, and document the corrective actions taken to address them. The requirements of this Monitoring Plan would be documented in a Condition of Approval for the project.
A comment was received regarding the location of the nearest residential receptor being mistakenly noted as 17 feet from the proposed drilling location. As noted on page 31 of the Draft EIR and page 53 of Draft EIR Appendix B (Noise Assessment and Peer Review), the estimated vibration levels were measured at the closest adjacent property line to the drilling location at the southwest corner of the site, which is approximately 17 feet from the drilling equipment. Noise and vibration impacts are typically measured at the adjacent property line, as that provides the most conservative estimation of potential impacts to surrounding receptors. As noted by the commenter, Attachment 13
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the nearest residence is approximately 90 feet from the drilling location and would, therefore, experience vibration levels substantially below both the 0.25 ips structural threshold and the 0.04 ips human annoyance threshold used for nighttime drilling as it is located further away from the drilling equipment than the property line.
C
omments were received regarding the particular vulnerabilities of surrounding residences given the possibility that some of the residences may have unreinforced slab foundations and large glass panels that could be more susceptible to vibration induced impacts. As discussed above, the threshold utilized in the Draft EIR was chosen based on the general characteristics of the surrounding residences and the experience and expertise of the technical consultants. No substantial evidence has been provided to illustrate that a lower threshold is more appropriate for the surrounding residences than the threshold identified in the Draft EIR. Argument, speculation, and unsubstantiated opinion or narrative do not constitute substantial evidence under CEQA. In addition, the estimated maximum vibration level at the closest adjacent property line was 0.03 ips, which would be below any of the other alternative thresholds for potential structural damage that were considered for the project.
A
comment was received questioning the validity of the Draft EIR Appendix B (Noise Assessment and Peer Review) utilizing data from 1995 to estimate potential vibration impacts resulting from the project. The Noise Assessment inadvertently referenced the 1995 version of the Transit Noise and Vibration Impact Assessment Manual from the FTA instead of the correct source, which was the 2018 version of the FTA’s Transit Noise and Vibration Impact Assessment Manual. Therefore, the most recently available version of the FTA’s manual was used for the project’s analysis.
A
comment was received questioning the validity of the vibration modeling as the reference data used to estimate vibration levels at surrounding receptors were based on, “BAENC File Data for similar equipment,” and no additional details were provided to allow for third-party verification.
The drilling rig vibration velocity level data utilized in the modeling for this project was derived from measurements of a Taylor RT-4000 series drill rig that was operating in Moreno Valley, California in 2021. The vibration levels associated with operation of this drill rig and associated ancillary equipment (e.g., motors, fans, etc.) were determined to be representative of the drilling equipment anticipated for the proposed project due to the similarities in well characteristics and construction needs. The vibration analysis included in Draft EIR Appendix B (Noise Assessment and Peer Review) was peer reviewed by the City’s technical consultant. As discussed below in Section VII Vibration Modeling, using comparable reference measurements to estimate potential noise and vibration levels for a project when exact specifications are unavailable is a standard industry practice that provides a reasonable estimate for anticipated noise and vibration levels that could result from implementation of a project. Because this is a standard industry practice, the references to the proprietary nature of the data were not noted as a deficiency of the Noise Assessment in the associated peer review.
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VIII. Noise Modeling
Comments received pertaining to the noise modeling prepared for the site included:
• The lack of additional mitigation measures to reduce nighttime noise levels at two adjacent receptors
• The proprietary nature of the reference noise data
• Equipment selected for the modeling
• The limitations of the peer review given the proprietary nature of the reference noise data • Interior noise levels at residences
• Lack of analysis for Coventry Court and Kingfisher Way residents • The lack of discuss regarding potential aeration noise from operation of the project • The validity of the provided ambient noise measurements
The comment stating that Table 7-3 in the Noise Assessment and Table 3.1-4 in the Draft EIR show that the nighttime noise level at two adjacent property lines would be above the applicable threshold during drilling activities, even after implementation of mitigation measure MM NOI-1.1, is correct. Page 27 of the Draft EIR notes that no other feasible mitigation measures are available that would clearly lessen the noise levels from drilling and includes an additional mitigation measure (MM NOI-1.2 below) to provide the opportunity for the occupants of the two residences exposed to significant and unavoidable nighttime drilling activity noise levels to relocate elsewhere during the significant, unavoidable nighttime drilling activity. Mitigation measure MM NOI-1.1 requires extensive noise barriers to be erected around the property boundaries and drilling equipment. This array of barriers is the maximum amount of feasible attenuating materials that can be provided on- site given the space needed to accommodate the necessary construction equipment, materials, and staff required to complete the drilling activities. Since the applicable nighttime threshold would still be exceeded at two residences even with implementation of mitigation measure MM NOI-1.1, this impact is acknowledged as significant and unavoidable in the EIR.
A comment was received questioning the validity of the noise modeling as the reference data for the 10 pieces of equipment that were included in the noise modeling for the project were based on, “BAENC File Data for similar equipment,” and no additional details were provided to allow for third- party verification. The reference noise data utilized in the modeling for this project was derived from measurements of a Taylor RT-4000 series drill rig that was operating in Moreno Valley, California in 2021. The noise levels associated with operation of this drill rig and the associated ancillary equipment (e.g., motors, fans, etc.) that were listed in Draft EIR Appendix B (Noise Assessment and Peer Review) were determined to be representative of the drilling equipment anticipated for the proposed project due to the similarities in well characteristics and construction needs. This equipment is typical of what would be in operation during the drilling of a groundwater well utilizing the reverse rotary well drilling method; which, as discussed in Section V Project Objectives and Alternatives Analysis, was determined to be the type of drilling method required for Attachment 13
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the proposed project. Since alternative drilling methods were determined to be infeasible for the project, those drilling methods and the equipment associated with them were not included in the noise modeling or Draft EIR.
A
comment was received questioning the validity of the peer review completed by the City’s consultant since the peer review did not address the reference data provided in the Noise Assessment. The primary purpose of the peer review is to confirm that the appropriate methodology, approach, and analysis was completed to support and substantiate the conclusions in the provided assessment. Exact specifications for the drilling rig that would be utilized for the project were not available during noise and vibration modeling for the project. Therefore, noise and vibration levels for the project were estimated based on archived field measurements for a comparable water well drilling project. Using comparable reference measurements to estimate potential noise and vibration levels for a project when exact specifications are unavailable is a standard industry practice that provides a reasonable estimate for anticipated noise and vibration levels that could result from implementation of a project. Because this is a standard industry practice, the references to the proprietary nature of the data were not noted as a deficiency of the Noise Assessment in the associated peer review. In addition, although details were not included in the table regarding the specifics of the reference equipment, the individual sound power level for all pieces of equipment were included to clarify the noise level inputs assumed for the listed equipment.
A
comment was received noting that the Draft EIR did not include estimated noise levels inside adjacent residences and instead limited the noise analysis and comparison to thresholds to exterior property lines. This is because the City’s thresholds for temporary and permanent noise impacts are measured at adjacent property lines, not the interiors of neighboring structures. Therefore, calculating estimated noise levels at the interior of adjacent residences and accounting for the individual design features of surrounding residences (e.g., large glass panels and lack of air conditioning) was not necessary, and was not included in the Draft EIR. However, as shown in Figure 7-4 of Draft EIR Appendix B (Noise Assessment and Peer Review), noise levels are expected to drop as measured further away from the drilling equipment on-site. Therefore, noise levels at th e
e
xterior of the adjacent residences would be lower than what is estimated at the property lines in the Draft EIR. One of the commenters noted that the original single-pane glass included on several surrounding residences would provide approximately 18 to 22 decibels of sound attenuation, which would further reduce the anticipated noise levels at the interior of each residence.
A
comment was received stating the Draft EIR only considered impacts to two of the adjacent residences and did not consider impacts to residents of Coventry Court or Kingfisher Way. As noted in Table 3.1-3 and on Figure 3.1-2 of the Draft EIR, estimated noise levels were provided for nine receptors, including the neighboring residential properties on Carlisle Way, Kingfisher Way, and Coventry Court.
A
comment was received regarding the potential operational noise generated by the project related to the sound of water aerating within the water tank. The commenter is correct that Draft EIR Attachment 13
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Appendix B (Noise Assessment and Peer Review) and the operational noise discussion on pages 30 to 31 of the Draft EIR focused on the mechanical equipment on-site, as the operational noise from the project would be generated primarily by the pump station’s booster pump and pump motor. No active power mixer (aerator) is proposed within the tank. The Draft EIR assumed that the water would be discharged into the 17-foot-tall water tank from a point close to the top of the tank and allowed to “splash”, which would agitate the water and expedite aeration in a passive manner.
However, the exact design of the tank has not been finalized. In other recent tank replacement projects within the City (e.g., LAS 30 on Winstead Court and LAS 31 on Selo Drive), the water tanks have had the fill line from the groundwater well discharge into the tank with an elevated inlet near the top of the tank and a ground level inlet. Splashing from the elevated inlet may occur for passive aeration in the water tank on-site; however, the sound would be enclosed and dampened within the tank because the tank is fully enclosed and constructed of thick steel. Based on the anticipated operations of the groundwater well and water tank, the water tank would be filled quickly, as needed, and the minimal splashing sounds would be limited to short periods of time. In addition, as noted on pages 30 to 31 of the Draft EIR, the anticipated increase in ambient noise levels at adjacent receptors during operation of the mechanical equipment associated with the project would range from zero to 2.2 dBA, which is well below the City’s identified threshold of significance of five dBA or more for increases in ambient sound levels. Therefore, the minor amount of potential operational noise generated from the water being placed in the water tank during project operations would not be a significant contributor to noise in a manner that would result in a significant operational noise impact (i.e., its noise contribution would not result in a total operational ambient noise increase of five dBA or more).
A
comment was received regarding a belief that the ambient noise levels measured and disclosed in Draft EIR Appendix B (Noise Assessment and Peer Review) and the Draft EIR are incorrect and show an existing noise level that is higher than the real conditions on-site. The ambient noise levels measured and disclosed in Draft EIR Appendix B (Noise Assessment and Peer Review) were collected in accordance with industry standards by technical acoustic experts with professional- grade equipment. The reported ambient noise levels were rigorously peer reviewed by the City’s consultant to confirm that the appropriate approach and methodology were utilized, and clarifications were provided in a revised report that was confirmed to be adequate by the City’s independent consultant. No substantial evidence has been provided to illustrate that ambient noise levels at the identified receptors are lower than what was disclosed in the Draft EIR and supporting technical documentation. Argument, speculation, and unsubstantiated opinion or narrative do not constitute substantial evidence under CEQA.
IX. Mitigation Monitoring and Reporting Program (MMRP)
Comments received pertaining to the MMRP included:
• S
tatement regarding future certification of the EIR by City Council Attachment 13
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A copy of the draft MMRP was uploaded to the City’s website with a statement regarding certification of the EIR for the 800 Carlisle Way Well and Water Tank project at the planned City Council hearing date in April 2026. This version of the draft MMRP was replaced with a version that includes placeholder date to be completed if the EIR is certified and the project is approved. A similar comment was received and addressed in the March 9, 2026 staff memo.
X. 2016 Well Destruction
Comments received pertaining to the former groundwater well on-site included:
• R
eversing the capping of the former groundwater well
• Details regarding the capping and destruction of the former groundwater well • Details regarding regulatory compliance in 2016 destruction • Impacts of destroyed well in relation to the proposed well T
he EIR describes the former groundwater well on-site as having been “capped,” “decommissioned,” and “destroyed” in 2016. The former groundwater well was permanently capped with cement to a depth of 700 feet, as noted by a comment. The former groundwater well was decommissioned, capped, and destroyed due to sanding issues and casing deterioration within the well and, therefore, is no longer functional (Draft EIR pages 8-9). Response E.7 in the Final EIR provided additional clarification:
T
he original groundwater well on-site, which was decommissioned and destroyed in 2016, was experiencing structural deterioration of the well casing and screen that led to excessive sanding in the well. The design of the original groundwater well, and other wells of that era, typically allowed for a useful service life of approximately 50 years. In 2016, the original groundwater well was 57 years old, and the deteriorated condition of the well at that time was typical of wells that have surpassed their useful service life, and was not due to adverse subsurface conditions.
T
he former groundwater well was decommissioned as it was experiencing structural deterioration.
To protect the groundwater and prevent groundwater contamination, the former well was capped.
The cap on the former well was a permanent cap, that is, the well was completely filled with cement. For reference, a well can be temporarily capped with a removable, watertight lid that prevents groundwater contamination while allowing for future re-use. When a groundwater well is destroyed, it has been permanently and properly filled, sealed, and closed so that it cannot be used again. Pursuant to California Water Code Section 13751, the construction, alteration, or destruction of a water well must file with the California Department of Water Resources (DWR) a report of completion within 60 days of the completion of the work. The applicant completed the work on July 27, 2016. The California Department of Water Resources completed the its review and processing of the Well Completion Report for this work and a permit was issued from Valley Water to cap and destroy the former groundwater well on-site. For these reasons, the comment suggesting the capping of the existing groundwater well on-site is reversible is incorrect.
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As the former groundwater well has been properly destroyed and the project does not propose any changes to the destroyed well, it would remain on-site as is under the proposed project. The presence of the destroyed well on-site would not have impacts if the proposed water well is installed and operating because it has been properly capped with inert, impermeable material (i.e., concrete). The entirety of the former well has been filled. No groundwater can be extracted from the former well. The proper destruction of the former well ensures no underground voids exist that could cause collapse or other geological or hydrological issues if the proposed well is constructed and operated. Contrary to one of the comments received, the location of the destroyed well on-site was identified as a constraint for the location of the proposed groundwater well on pages 9 and 40 of the Draft EIR, where it was noted that the proposed well would need to be set back 50 feet from the existing, destroyed well location on-site.
As discussed in the EIR (page 98 of the Initial Study included as Appendix A) and the Sustainable Groundwater Management Technical Memorandum (Initial Study Appendix D) prepared for the project, there are 26 listed cleanup sites within one mile of the project site, two of which are open cases where the most recent groundwater sampling has shown that concentrations of constituents of concern (COCs) were below the applicable Environmental Screening Levels (ESLs), and one of which is a closed case whose contaminated plume extent is primarily limited to the property boundaries. Based on the distance, location, and level of contamination at those three sites, pumping operations at the proposed well on-site would not mobilize or cause migration of existing contaminants at those sites and the project would have a less than significant impact on groundwater quality.
The analysis and conclusions in the EIR are supported by substantial evidence (e.g., facts, reasonable assumptions predicated on facts, and expert opinion supported by facts). Comments noting potential impacts to groundwater, aquifer integrity, and cross-contamination between aquifers due to the former well and proposed well were unsubstantiated. Comments regarding California Water Code Section 231 are not applicable to the project or project site as it pertains to improperly constructed, abandoned, or defective wells. The former groundwater well was properly destroyed and the proposed well (if approved) would be constructed in accordance with applicable laws and regulations and obtain necessary permits (including permits from Valley Water).
XI. Mitigation measures for construction noise
Comments received pertaining to the mitigation measures for construction noise included:
• Significance level of the nighttime construction noise (due to drilling) that would occur outside allowed construction hours
• Provision of hotel vouchers being mitigation under CEQA • Provision of hotel vouchers only limited to the two significantly impacted residences • The need for monitoring during the drilling phase
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S
imilar comments were received and responded to in the March 9, 2026 staff memo regarding mitigation requiring ongoing noise monitoring during the demolition, grading, excavation, trenching, and tank construction phase and not during the drilling phase. As explained in the March 9, 2026 staff memo, mitigation measure MM NOI-1.3 (which is to conduct ongoing noise monitoring at the property boundaries during the demolition, grading, excavation, trenching, and tank construction phase) is required because the technical modeling for these phases assumed that all construction equipment would be in operation simultaneously during these phases. This is a conservative assumption and results in a conservative (i.e., more impactful) analysis because it is highly unlikely that construction activities would be managed this way on-site. Since various pieces of equipment would be operating at different times and moving around the site, it is difficult to predict the exact noise levels that would be experienced at each property line. For this reason, conservative modeling was completed and a conservative, significant impact was identified in the EIR. Given the reality of construction activities (e.g., various pieces of equipment operating at different times and moving around the site), however, it is anticipated that the noise generated during the demolition, grading, excavation, trenching, and tank construction phase on-site would not likely exceed the applicable threshold of significance. Therefore, ongoing, real-time noise monitoring at the property boundaries is included. If noise levels during these construction activities are measured within one dBA of the 80 dBA threshold at surrounding sensitive receptors, mitigation measure MM NOI-1.3 requires portable acoustic barriers be installed between the noise generating equipment and the impacted sensitive receptor prior to initiating any additional noise generating construction activities. Conversely, because the modeling for the drilling activities is not as variable or based on conservative assumptions, no ongoing noise monitoring is required and the calculated maximum estimated noise levels disclosed in the Noise Assessment are expected during drilling activities.
H
owever, as requested by the City of Sunnyvale Planning Commission, the applicant has prepared a Monitoring Plan that includes noise and vibration monitoring, along with a public reporting program that would be implemented throughout the drilling activities on-site. The public reporting program would provide transparent information to the City and neighboring residents daily and identify any exceedances of applicable noise or vibration thresholds, describe the source of the exceedances, and document the corrective actions taken to address them. The requirements of this Monitoring Plan is documented in a Condition of Approval for the project.
I
f the project is approved, the City is required to adopt a Mitigation Monitoring or Reporting Program (MMRP) to ensure the identified mitigation measures in the EIR (including mitigation measure MM NOI-1.1 requiring the installation of acoustical barriers during drilling activities on- site) are implemented. The mitigation measures identified in the EIR are feasible. The acoustic barriers identified in MM NOI-1.1 are required to meet the performance standards identified in the measure, have been implemented for similar construction projects proximate to sensitive receptors, are commercially available, and are technologically capable of the noise reduction stated in the EIR. No substantial evidence was provided in the comments that the mitigation measures (such as MM NOI-1.1) are infeasible.
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A comment was received that the project’s significant and unavoidable nighttime construction noise (due to drilling) that would occur outside allowed construction hours is not mitigated to the fullest extent feasible. The EIR includes mitigation measures MM NOI-1.1 (installation of acoustic barriers) and MM NOI-1.2 (provision of vouchers for alternative accommodations) to address the significant, unavoidable impact to the extent feasible. A comment was made that mitigation measure MM NOI-1.2, which requires the applicant to offer vouchers to the significantly impacted residences for alternative accommodations, should not be considered mitigation under CEQA and does not meet the definition of mitigation in CEQA Guidelines Section 15370. Per CEQA Guidelines Section 15370:
“Mitigation” includes:
(a) Avoiding the impact altogether by not taking a certain action or parts of an action. (b) Minimizing impacts by limiting the degree or magnitude of the action and its implementation. (c) Rectifying the impact by repairing, rehabilitating, or restoring the impacted environment. (d) Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.
(e) Compensating for the impact by replacing or providing substitute resources or environments, including through permanent protection of such resources in the form of conservation easements.
The provision of vouchers would compensate (i.e., pay for) the residents at the significantly impacted residences (819 and 823 Coventry Court) to relocate to an alternative accommodation (i.e., substitute environment) for the duration of the (temporary) significant, unavoidable impact that would occur at their residences. As such, MM NOI-1.2 is a mitigation measure under CEQA. The mitigation describes how vouchers would be provided for the specific dates that nighttime drilling activities are scheduled, in accordance with the finalized construction schedule. As discussed earlier, the implementation of this mitigation measure does not reduce the significant, unavoidable noise levels at these two residences to an acceptable level and the City cannot require the residents of the significantly impacted residences relocate. Therefore, the impact from nighttime construction noise that would occur outside allowed construction hours would remain significant and unavoidable.
A comment noted that mitigation is required during nighttime drilling activities and no measures are required during other hours of drilling activities. Because the noise generated by the drilling would not exceed the significance thresholds during the allowed construction hours or the outside allowed construction hours with the implementation of mitigation measure MM NOI-1.1 (installation of acoustic barriers), no additional mitigation can be required during those timeframes under CEQA. However, it should be noted that, while the purpose of the vouchers is to provide alternative accommodation during the significant nighttime drilling activities, in theory, the voucher for nights at in hotel room would allow for daytime hours in the hotel room as well.
In addition, as explained in the Final EIR (including in Response E.4 on page 13 and Response E.14 on page 20 of the Final EIR), while not required under CEQA, the applicant has agreed to provide all other residents adjacent to the site with the same opportunity to temporarily relocate during Attachment 13
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nighttime drilling. The provision of hotel vouchers to the other residents adjacent to the site would be required as part of a Condition of Approval by the City in the development permits for the project.
C
omments asserting the EIR does not contain findings that nighttime construction noise (due to drilling) that would occur outside allowed construction hours is mitigated to a less than significant level are correct. As explained in the EIR, because the implementation of these two mitigation measures would not reduce the significant, unavoidable noise level at impacted residences to an acceptable level and no other feasible mitigation measure is available that would lessen the impact, the impact was concluded and disclosed in the EIR to be significant and unavoidable (see pages x, 23, 27, 28, 36, 37 in the Draft EIR). In addition, the comments did not provide substantial evidence identifying a feasible mitigation measure considerably different from others previously identified in the EIR that would clearly lessen this significant, unavoidable impact.
XII. Depth of the Destroyed Well
Comments received pertaining to the depth of the destroyed well on-site included:
• T
he omission of this information in the EIR.
• Th
e importance of this information to address groundwater impacts, aquifer penetration and potential inter-aquifer connectivity, compliance with the Sustainable Groundwater Management Act, and the alternatives analysis.
T
he commenter is correct that the depth of the decommissioned well does not appear in the EIR, nor does it appear in the Initial Study (Appendix A to the Draft EIR). The omission, however, does not render the EIR inadequate as explained below.
G
roundwater quality impacts that could result from implementation of the project are discussed on pages 98-99 of the Initial Study (Appendix A to the Draft EIR). The discussion is based on existing and post-project surface area, existing condition of the subbasin, and historic data on aquifer and subbasin inflow and outflow. Cal Water would obtain the necessary permits from Valley Water to pump groundwater from the subbasin. Valley Water, who is responsible for managing the sustainability of groundwater levels in the subbasin, reviewed the EIR for the project and did not find the analysis inadequate. Disclosing the historical depth of the decommissioned well is not necessary as that historic well is no longer in operation and, therefore, has no effect on the groundwater impact analysis.
T
he project’s potential impacts on the aquifer underneath the site are discussed primarily in Sections 4.7 and 4.10 of the Initial Study (Appendix A to the Draft EIR). As explained in the Initial Study, based on the estimated annual yield of the proposed well and the historic pumping data for the Santa Clara Subbasin, it was determined that the project would have less than significant impacts regarding subsidence, groundwater contamination, and groundwater supplies. Disclosing Attachment 13
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the historical depth of the decommissioned well is not necessary as that historic well is no longer in operation and, therefore, has no effect on the aquifer conditions.
The Sustainable Groundwater Management Act (SGMA) requires local agencies to form groundwater sustainability agencies (GSAs) for high and medium priority basins. These GSAs are required to develop and implement groundwater sustainability plans (GSPs) to avoid undesirable results and mitigate overdraft within 20 years for the identified basins. The GSA for Santa Clara Valley is Valley Water, and the project’s compliance with the applicable Groundwater Management Plan (GWMP) prepared by Valley Water is included on pages 100 to 101 of the Initial Study (Appendix A to the Draft EIR). The historical depth of the decommissioned well does not affect the project’s compliance with the GWMP. In addition, Valley Water reviewed the Draft EIR, including the Initial Study, and did not have any comments pertaining to the discussion of the project’s consistency with the SGMA or GWMP.
Pursuant to CEQA, the alternatives analysis in the Draft EIR is intended to identify potential alternatives that would feasibly attain most of the basic objectives of the project but avoid or substantially lessen any of the significant effects of the project. Three alternatives were evaluated in Section 7.2.2 of the Draft EIR (including a Shallower Well Depth On-Site alternative) and several others in Section 7.2.1 of the Draft EIR were considered but rejected from further analysis. The historical depth of the decommissioned well on-site is not necessary to identify and evaluate a reasonable range of alternatives for the project that attains most of the basic objectives of the project and avoids or substantially lessens the project’s significant effects.
The above comment provides no substantial evidence that the project would result in a new significant environmental impact that was not disclosed in the Draft EIR, nor does it identify a feasible project alternative considerably different from others analyzed in the Draft EIR that would clearly lessen the environmental impacts of the project. For these reasons, no further response is required.
XIII. Miscellaneous Items
Several comments unrelated to the CEQA analysis were received, these included:
• How the project would mitigate potential fire risks from construction activities • Whether security would be provided during construction
In general, the California Fire Code (Title 24, Part 9) Chapter 33 (which correlates to Chapter 33 of the California Building Code) outlines general fire safety precautions for all structures in the course of construction, alteration or demolition, including those in underground locations. The requirements (including developing a site safety plan establishing a fire prevention program at the site that includes training and fire protection equipment on-site) seek to maintain required levels of fire protection, limit fire spread, establish the appropriate operation of equipment and promote Attachment 13
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prompt response to fire emergencies. Compliance with National Fire Protection Association (NFPA) 241 is required for items not specifically addressed in the California Fire Code. Cal Water has standard technical specifications that will be required of any contractor operating on-site to reduce the potential risks of fires during construction activities and include the following:
Fire Prevention and Protection: The Contractor shall perform all work in a fire -safe manner. He shall supply and maintain on the site adequate fire-fighting equipment capable of extinguishing incipient fires.
The Contractor shall comply with applicable federal, state, and local fire -prevention regulations. Where these regulations do not apply, applicable parts of the National Fire Prevention Standard for Safeguarding Building Construction Operations (NFPA No. 241) shall be followed.
Se
curity would not be provided on-site during the full duration of construction. The project site is currently fenced, and the proposed sound walls required as part of mitigation measure MM NOI-1.1 would be installed would enhance site security during drilling activities. Personnel would also be on- site during the 24/7 drilling activities.
Conclusion
The late comment letters received and included in Attachment A do not provide substantial evidence that the project would result in a new significant environmental impact that was not disclosed in the Draft EIR, nor does it identify a feasible project alternative considerably different from others analyzed in the Draft EIR that would clearly lessen the environmental impacts of the project. For this reason, pursuant to CEQA Guidelines Section 15088.5, recirculation of the EIR is not required.
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