OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.
CITY DISTRIBUTION DIVISION
1990 Newcomb Avenue
San Francisco, CA 94124
T 415.550.4900
DATE: March 22, 2022
TO: Commissioner Anson Moran, President
Commissioner Newsha Ajami, Vice-President
Commissioner Sophie Maxwell
Commissioner Tim Paulson
THROUGH: Dennis Herrera, General Manager
Steven R. Ritchie, Assistant General Manager, Water
FROM: Bill Teahan, City Distribution Division Manager
Angela Cheung, Water Supply and Treatment Division Manager Andrew DeGraca, Water Quality Division Manager
SUBJECT: Water Pipeline Assessment: July 1, 2021 through December 31, 2021
Purpose
This memorandum captures the noteworthy maintenance and construction activities that the City Distribution, Water Supply & Treatment, and Water Quality Divisions performed to the linear assets during the period of July 1, 2021 through December 31, 2021.
I. Lead Occurrence/Pipeline Material
In 2016, the California Senate enacted SB-1398 “Public Water Systems: Lead User Service Lines” which compelled water agencies to compile an inventory of user service line materials with confirmed or possible lead components. Water agencies were required to report on inventory findings to the State by July 1, 2018. Furthermore, by July 1, 2020, agencies were obliged to confirm the existence or absence of lead components on user service lines and submit a timeline for replacement of all user service lines with confirmed or potential lead components. 1
In response to SB-1398, the SFPUC City Distribution and Water Quality Divisions created the Lead User Service Line (LUSL) program that was designed to implement strategies and tools to catalog, identify and compile user service line materials including a statistical analysis and field inventory of user service line materials, field verification and inspections, replacement of affected user service lines and water quality sampling for buildings and residents affected by the service line replacement.
1 In 1991, the United States Environmental Protection Agency (EPA) published the Lead and Copper Rules (LCR) to reduce exposure to lead in drinking water. The 2014 Flint Michigan tap water lead contamination crisis prompted the U.S. Congress to direct t he EPA to obtain recommendations from the National Drinking Water Advisory Council (NDWAC) for LCR revisions. In 2015, the NDWAC published recommendations for LCR Revisions, most notably the recommendations requiring water agencies to create inventories of all lead service lines and replace all lead service lines by 2030.
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A. Inventory of Service Line Materials
In the 1980s, the SFPUC proactively removed all pipes and water service lines that were known to have been fabricated with lead. As a result, the majority of the SFPUC’s water user service lines consist primarily of copper, plastic, and iron.
However, out of the 176,028-retail customer user service lines within the City and County of San Francisco, SFPUC records indicated that 8,848 user service lines (5%) were of unknown material type (aka “unknown services”), and 4,434 (2.4%) user service lines were recorded as galvanized steel. Consequently, all unknown and galvanized steel service lines will need to be field verified to ascertain and confirm the actual material type. Additionally, all service lines that have been field investigated and found to be made of galvanized steel will then be replaced with copper because galvanized steel water services are commonly connected to water distribution pipes through a short flexible connection pipe made from lead. This flexible connection pipe is often referred to as a goose neck, pig tail or lead whip.
Figure 1 demonstrates a typical galvanized water service line with a gooseneck/pig tail/lead whip.
Figure 1
Typical Water Service Line with Gooseneck/Lead Whip Diagram
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As of December 31, 2021, 6,582 (74%) of unknown user service lines and 2,551 (58%) of galvanized user service lines have been field inspected. Based on current trends, all field investigative work is expected to be completed no later than September 2022. The results of the field investigations are in Tables 1 and 2, below:
Table 1
Unknown Service Field Investigation Results
Field Identified
Material Quantity %
Galvanized 294 5%
Lead 0 0%
Other materials* 6,288 95%
Total 6,582 100%
Table 2
Galvanized Service Field Investigation Results
Field Identified
Material Quantity %
Galvanized 555 22%
Lead 0 0%
Other materials* 1,996 78%
Total 2,551 100%
Tables 1 and 2 reveal that 95% of unknown user service records and 78% of galvanized service records are comprised of copper. As of December 2021, 9,133 field inspections have been completed and 4,007 field inspections remain. See Graph 1 for a timeline of field investigations.
Graph 1
Water Service Line Material Investigations
0 2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000Total Field Inspections
Actual Sampled Orignal Schedule At current rate
13,140 Total by Sept 2022
Current: 9,133
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B. Replacements of Galvanized Service Lines
Of the 849 confirmed galvanized service lines, 120 or 14% have been subsequently replaced with copper, while the remaining lines will be scheduled for replacement.
See Map 1 for the 120 locations.
Map 1
Galvanized Service Lines Replaced with a Copper Service
The confirmed galvanized service line replacements have been scheduled with the intention of prioritizing schools and licensed childcare facilities. All schools and licensed childcare facilities have already been field investigated and thirteen confirmed galvanized service lines have been replaced with a copper service line. It has been determined that all thirteen schools and/or licensed child-care facilities have no lead whips. See Table 3 for a list of the thirteen schools and licensed child- care facilities.
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Table 3
Schools and Licensed Childcare Facilities with a new Service Line
No. Name of School Address Lead Whip
1 Stratford Schools Inc. 301 De Montfort Ave.
None
2 Ninth Church of Christ 175 Junipero Serra Blvd.
3 St Francis Episcopal Church 399 San Fernando Way
4 Nihonmachi Little Friends 1830 Sutter St.
5 Chinese American International School 42 - 52 Waller St. 6 Department of Human Services childcare 200 Cashmere St. 7 Real Estate Department Childcare 50 Raymond Ave.
8 Crayon Box Preschool 3215 Cesar Chavez St.
9 St. Anne’s Convent 1330 14th Ave.
10 St. Anne’s Church 850 Judah St.
11 St. Anne’s Church Rectory 850 Judah St.
12 San Francisco Chinese Baptist Church 1811 34th Ave.
13 St. Thomas Apostle School 3801 Balboa St
Upon completing the service line replacements for all 13 schools and licensed childcare facilities, 107 identified galvanized service lines were subsequently replaced for a total of 120 replacements through December 31, 2021. The rate of service line replacements has increased significantly over the last six months; 78 replacements were completed during this reporting period which is 65% the total 120 galvanized services renewed since the start of the renewals in 2018. 78 replacements is an increase of 66 services, or 550%, from the previous fiscal year, FY 21, which had twelve replacements. See Graph 2 which shows the rate of galvanized service replacements by fiscal year.
Graph 2
Galvanized Service Line Replacements by Fiscal Year
1 29
12 78
0 10
20 30
40 50
60 70
80 90
FY 19 FY 20 FY 21 FY 22
Total Service Renewals
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Of the 120 replaced galvanized services, only 30, or 25%, had lead whips while the remaining 90 did not contain any lead whips or fittings. Based on the 120 replacements, only 25% of galvanized services are projected to be actual lead service lines.
On July 1, 2020, the SFPUC submitted a final report to the State containing the results of the on-going field investigations, a 10-year capital plan replacement program, and a schedule for field investigating the remaining unknown and galvanized user service line records. As of this reporting period, the SFPUC is on schedule with its field investigations.
To finalize the replacement of all galvanized service lines within the next five years, the SFPUC is developing and implementing a contract that will utilize a contractor to perform all earthwork and ancillary tasks associated with service line replacements.
The contract will be designed to alleviate the resource load for the SFPUC and allow crews to effectively mobilize and replace service lines in an expeditious manner. It is projected that the SFPUC will replace approximately 1,578 galvanized user service lines within the contracting period. All homeowners affected by a user service line replacement will receive a notification that includes educational material about health impacts of lead as well as the service line replacement process. Additionally, a water pitcher and filters will be distributed to each homeowner and resident before the service line is replaced. Service line flushing and follow-up water quality monitoring will commence after the water service has been replaced.
C. Lead and Copper Rule Revisions
On January 15, 2021, the U.S. Environmental Protection Agency (EPA) published the first Lead and Copper Rule Revisions (LCRR) which marks the first major update since the rule was created in 1991. On June 10, 2021 the EPA signed a final rule to extend the effective date of the Lead and Copper Rule (LCR) to December 16, 2021 with a compliance deadline of October 16, 2024.
The newly enacted LCRR defines the “service line” as the portion of the water line that extends from the building inlet (not the water meter) to the water main and requires water systems to complete an inventory of the service lines regardless of ownership. The LCRR service line definition contrasts with SB-1398 which defines the user service line as the portion from the water meter to the water main.
Therefore, the LUSL program will focus its efforts on identifying strategies and a plan to inventory the customer side of the service line that extends from the water meter to the building inlet and entail the inspection of approximately 168,867 customer side service lines.
As of December 31, 2021, 4,002 customer service lines have been field inspected.
The results of the field investigations are in Table 4 below.
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Table 4
Customer Service Field Investigation Results
Field Identified
Material
Customer Service
Material %
Copper 3,691 92.2%
Plastic 5 0.1%
Galvanized 306 7.7%
Total 4,002 100%
The USEPA noted its intent to promulgate a new Lead and Copper Rule Improvements (LCRI) rule by October 2024. The LCRI could require additional work including work related to the customer side of the water service line.
The recently enacted LCRR requires water agencies to make publicly available all lead service line inventory findings. Therefore, the SFPUC has created and posted an interactive map that displays customers who have been identified to have either an unknown or galvanized water service. The map is updated every six (6) months and can be accessed at: https://sfpuc.org/accounts-services/water-quality/lead.
D. Water Quality Sampling
In 2019, the Water Quality Division (WQD), in coordination with SFUSD, Archdiocese of San Francisco and early education facilities, completed lead testing at public and private schools. A total of 10 schools (6 public and 4 Archdiocese) was found to have at least one tap containing lead concentrations exceeding the State Water Resources Control Board’s Action Level of 15 parts per billion (ppb). The SFUSD and the Archdiocese of San Francisco addressed this issue and made all necessary improvements to the water lines. The LCRR will require new rounds of school and early education facility testing beginning in 2025.
During this period, WQD also enlisted customers who were scheduled to replace their galvanized service with a lead whip to partake in a voluntary assessment of lead in the building’s drinking water. A total of thirty-four households volunteered to have their water sampled before and after the galvanized service laterals were replaced.
To give a meaningful representation of lead whip removal impacts to household taps, up to four sets of sequential samples were conducted for each participating household at set intervals: prior to the removal of the lead whip, one week, one month and three months after the service was replaced. The sequential sampling represents water within the service lateral, household plumbing and kitchen tap before and after galvanized service line with flexible lead connection part replacement. Testing concluded at each of the thirty-four households either at the end of three months, or when lead levels were low or near detection limits after construction. As of December 31, 2021, twenty household sites were verified as having a lead whip.
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II. Pipeline Renewal and Replacement Program
A. Local Water Facilities
Capital improvement projects for the local water pipelines have decreased throughout this reporting period. Planning and design continued for several pipeline projects including seismic improvements to the College Hill Reservoir system.
1. Replacement Rate for FY22 (Q1 and Q2)
At the beginning of FY22 (Q1), the anticipated mileage for distribution system pipeline replacement was projected to be 7.5 miles, a decrease of 35% from the previously forecasted 11.5 miles. For the first two quarters of FY22, 2.1 miles of pipe have been replaced, a decrease of approximately 40-50% from the previous six months. Projects expected to begin construction in the second half of FY22 include Taraval B, Vicente Street, and Diamond Street. Several additional projects previously expected to begin construction have subsequently been delayed due to on-going challenges presented by the COVID-19 pandemic, project scheduling delays, and significant funding limitations.
Table 5
Water Main Replacement Projects*
Ductile Iron Pipe (DIP) and Earthquake Resistant DIP (ERDIP)
Project Contract No. Miles
FY22 Q1&Q2
8-Inch Ductile Iron Water Main Replacement on
Baker St. (Geary Blvd to Broadway St.), Sutter St.
(Divisadero St. to Presidio Ave)
WD-2616 0.31
Pavement Renovation, Sewer Replacement and
Water Main Replacement on Castro St. and 26th St. WD-2739 0.33 16-Inch & 36-Inch, and 8-Inch Ductile Iron Water
Mains at Various Locations on 19th Ave from
Holloway Ave to Lincoln Way
WD-2775 0.15
8-Inch Ductile Iron Water Main Replacement on
Casitas Ave (Lansdale Ave to Yerba Buena Ave)
and Dalewood Way (Lansdale to Sherwood Court)
WD-2842 0.93
Water Main Replacement for the Moscone
Expansion Project WD-2810.11 0.28
Geary Rapid East of Van Ness WD-2834 0.03
As-Needed Water Main Replacement at Various
Locations – No.2
WD-2819
0.07 Total 2.1 miles
* New water mains installed to support the Moscone Center Expansion project have been added to this reporting period since they were mistakenly left out of the final mileage reporting from FY21 and are included to be actualized for the FY22 reporting period.
2. Unit Construction Costs
Pipeline replacement program budget cost per mile to replace water distribution pipelines has increased 70% from $3.18 million to approximately $5.4 million.
The updated cost per mile for streetscape, transit, or ERDIP-type projects is approximately $8 million, an increase of approximately $1 million.
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The $3.18 million per mile was developed in 2011. Since that time, design, construction, and material costs have increased. Additionally, the updated cost per mile for water main replacement projects have been affected by:
a. The program has previously focused on replacing smaller, less expensive distribution mains to coordinate projects with the San Francisco Public Works’ (SFPW) Paving Program.
b. Projects have been including larger diameter pipe replacement for larger distribution mains as well as special earthquake-resistant pipe installation to increase seismic reliability of the City’s local water distribution.
c. Projects along designated State highway routes such as Van Ness Avenue, 19th Avenue, and Taraval Street are significantly more expensive due to State and Caltrans permitting and code requirements such as costly utility protection obligations and restricted work hour requirements.
d. Other changes in pavement restoration, ADA curb ramps, and permitting requirements within the City continue to increase pipe replacement project costs.
Graph 3 identifies the targeted versus actual miles of pipeline installed over the last ten fiscal years.
Graph 3
Miles of Pipeline Installed
-
2.0 4.0
6.0 8.0
10.0 12.0
14.0 16.0
FY12 FY13 FY14 FY15 FY16 FY17 FY18 FY19 FY20 FY21 FY22
Linear Miles
Target Miles Actual Miles
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WD-2842: Water Main Replacement Work on Sutter Street and Casitas Avenue
WD-2739: Water Main Replacement Work on 26th Street at Church Street
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3. Seismic Improvements
The College Hill Pressure System is one of the most critical domestic water distribution systems in San Francisco. This pressure system delivers water by gravity from College Hill Reservoir to customers in the mid-eastern strip of San Francisco including City Hall and San Francisco General Hospital (SFGH), the only Level I Trauma Center in the Bay Area that services 1.5 million residents of San Francisco and Northern San Mateo.
During a catastrophic earthquake event, underground utilities may be subject to potentially significant ground deformation and high seismic ground trembling loads. To be prepared for such an event, San Francisco will need to safeguard SFGH and City Hall so that its vital critical facilities will be operational and functional immediately after a natural disaster. The stability of these significant City hubs and buildings will likely be one of the most critical factors determining the outcome of the City’s emergency response and recovery from a natural disaster.
The College Hill Reservoir System Improvement Project (Phases 1 through 5) was developed and designed with the intent to utilize new pipe technologies and earthquake resistant pipe materials. Specifically, Kubota Earthquake Resistant Ductile Iron Pipe (ERDIP) was evaluated along with other available ductile iron pipe systems and the assessment was based on a.) a pipe’s ability to withstand large joint deflections b.) the pull-out resistance at joints, and c.) the capacity and capability of each joint to expand and contract. Based on the analysis, Kubota ERDIP was selected because of its high performance for deflection, pull - out resistance, and expansion/contraction capacity at joints. Table 6 shows the breakdown of phases and progress of improvements.
Table 6
College Hill Reservoir System Improvement Project
Project Phase Project Limits Miles Status
1 Various Streets in the vicinity of
SF General Hospital 0.6 Completed 2017
2 22nd St. (Valencia to Hampshire) 0.8 Completed 2019
3a College Hill Reservoir Outlet 0.2 Construction scheduled to begin March 2022
3b Prospect Ave. (Santa Marina to
Coso) 0.6 Construction scheduled to begin
June 2022
4 Precita Ave. (Coleridge to Cesar
Chavez) 0.7 Construction scheduled for Spring
2023
5 Hampshire St. (Cesar Chavez to
22nd St.) 1.2 Construction scheduled for Spring
2023
Total Miles 4.1
Phases 1 and 2 were completed in 2017 and 2019, respectively. Phase 3a has been awarded to Ranger Pipelines Construction and is scheduled to begin in March 2022. Phase 3b has been awarded to Cratus Inc. Construction and is scheduled to begin construction in June 2022. Phases 4 and 5 are currently in design.
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Map 2
College Hill Reservoir System Improvement Project
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B. New Water Service Applications
New water service applications include new water services (typically two to six individually metered water connections per address for water, fire, and irrigation services); installation and/or relocation of fire hydrants; and new main connections for large private developments (Hunter’s Point, Mission Bay, Warriors Arena, Treasure Island, Potrero Hope SF, and Candlestick Point). During this reporting period, a total of 192 new single service installation requests were received. Table 8 summarizes the number of new water service applications received during this reporting period as compared to previous periods.
Graph 4
New Water Service Applications
Graph 4 indicates that the number of single service install requests have decreased by approximately 16% from 2019 to present.
C. Emergency Firefighting Water System (EFWS) Infrastructure The SFPUC has the following EFWS projects under planning, design, and construction.
1. Planning and Design:
a. Westside Potable EFWS Pipeline: New potable EFWS pipeline located within the in Richmond and Sunset areas. Planning is currently in progress. The Alternative Analysis Report (AAR) was completed in July 2021. Conceptual Engineering Review (CER) is expected to be completed in August 2022.
b. Fireboat Manifolds:
a. Install a new fireboat manifold and pipelines at Fort Mason and near Pier 35.5. Planning is in progress. Conceptual Engineering Review is expected to be completed in December 2022.
233
263
230
194
181 191 192
0 50
100
150
200
250
300
July-Dec
2018
Jan-June
2019
July-Dec
2019
Jan-June
2020
July-Dec
2020
Jan-June
2021
July-Dec
2021
Number of Applications
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b. Install a fireboat manifold and pipelines on Terry Francois Blvd. in the vicinity of the Warriors Stadium Ferry Landing and on Treasure Island at the Ferry Terminal. Planning is in progress.
Conceptual Engineering Review is expected to be completed in December 2022.
2. Construction:
a. 19th Avenue Pipeline: Install a new 20-inch EFWS pipeline on 19th Avenue from Irving Street to Kirkham Street, a crossing at Ulloa Street, and a new 36-inch diameter welded steel Potable Emergency Firefighting Water Systems (PEFWS) pipeline on 19th Avenue from Vicente Street to Sloat Blvd as part of Public Works’ 19 th Avenue Roadway Improvements, Contract 2652J. Construction completion expected September 2023.
b. Clarendon Supply: Provide new EFWS water supply and pipeline near the crest of Clarendon Avenue at Dellbrook Avenue. Construction continues. Construction completion expected July 2022.
c. Terry Francois Blvd/Mission Rock/Warriors Way Pipeline: Install new 20” AWSS pipe on Terry Francois Blvd from Mission Rock Street to Warriors Way as part of SFPUC contract DB-129.1. Construction completion expected March 2022.
d. Pumping Station 2 Project: Improve the seismic performance of the Pump Station’s building structure. Construction expected be completed in December 2022.
e. Vicente Pipeline: Install a new 36-inch diameter PEFWS pipeline on Vicente from 19th Avenue to 25th Avenue. Constructed continues.
Construction completion expected July 2024.
19th Avenue Pipeline Project at Kirkham
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Clarendon Supply Project Terry Francois Blvd. Pipeline Project
Pumping Station 2 Project
D. Regional Water Facilities
Capital improvement projects for the regional pipelines progressed steadily during this reporting period. Planning and design continued for several pipeline projects that will replace and rehabilitate deteriorated pipe segments.
1. Planning and Design
a. Crystal Springs Pipeline No. 2 (CSPL2) Reach 5 from K40 – K50 (approximately 3.9 miles): CSPL2 is a 60-inch welded steel pipeline with coal tar lining. The scope of work for this project includes lining replacement, new manholes to improve access, a new in-line isolation
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valve, and appurtenance improvements to meet current water quality standards. During this reporting period, condition assessment was completed, and the Alternatives Analysis Report was finalized. The selected lining replacement option of cement mortar lining will be further refined during the Conceptual Engineering Report for issues related to environmental, right-of-way, constructability, hydraulic, and operational impacts. Consultant selection to complete the Conceptual Engineering Report is underway.
b. Bay Division Pipeline (BDPL) Nos. 1, 2, 3 and 4: The planning phase continued for this lining repair project. The scope of the project is to establish a contract to repair lining defects that were identified from previous inspections and lining defects expected to be identified in future inspections. When this contract is in place, maintenance inspection and lining repairs can be performed within the same shutdown, eliminating the need to perform a second shutdown to perform repairs.
The scope of work primarily consists of removing corrosion accumulation at pipe joints from spalled cement mortar lining, applying new cement mortar or dielectric lining, and cleaning debris and sediment found inside the pipe. During this reporting period, the Conceptual Engineering Report was finalized, and the project entered the design phase.
Safe pipeline isolation must be considered during project planning and design. Stantec was retained to perform a surge pressure analysis and alternatives analysis related to safe pipeline entry for SFPUC staff to support upcoming shutdowns.
c. Town of Sunol distribution pipeline (creek crossing upgrades):
The 12-inch pipeline, which crosses Arroyo de la Laguna in Sunol, was originally installed below the creek bed. However, with erosion over time, the pipeline is now completely exposed. This section of the pipeline feeds both the potable and firefighting water lines to the Town of Sunol. The geotechnical investigation and Conceptual Engineering Report were finalized during this reporting period. The design and environmental permitting work began for an open trench pipeline replacement crossing the creek.
d. CSPL2 Reaches 2 and 3: CSPL2, from valves K10 to K30 (approximately 5.3 miles), is a 60-inch welded steel pipeline with coal tar lining. Some of it traverses through steep terrain with narrow access, making maintenance and repair difficult. This project will replace and realign 1.5 miles of the pipeline and make improvements to the appurtenances to meet current water quality standards. The site survey, geotechnical study, and the development of the Conceptual Engineering Report continued in this reporting period. e. Bay Division Pipeline No. 4 (BDPL4): The planning phase continued for the repair and replacement of targeted Prestressed Concrete Cylinder Pipe (PCCP) segments between Valves D50 and
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D68. In 2017, an inspection found numerous circumferential cracks in the last 1.5 miles that parallel Edgewood Road in Redwood City.
These cracks were mostly small, with only a few that opened to
0.125-inch. While the circumferential cracks are not currently posing a risk of structural failure, leaks have developed over time due to corrosion of the inner steel cylinder believed to be a result of the circumferential cracks. In August 2020, an external condition assessment was performed for certain pipe segments to verify the number of broken prestressed wire wraps found in the 2017 inspection. The 2020 assessment was performed to verify the accuracy of the electromagnetic method of determining the number of wire breaks, and the result was a confirmation that the electromagnetic method was accurate.
In March 2021, BDPL4 was shut down to repair leaks caused by the circumferential cracks. WEKO-seals were installed to seal the leaks.
Condition assessment findings and recent leaks confirmed that both the broken prestressed wires and circumferential cracks need to be addressed. In September 2021, another leak was found in the same stretch of BDPL4. This was a new leak immediately downstream of a previously repaired leak. SFPUC staff suspected the pipeline going through wet and dry cycles could be causing new leaks to develop and decided against doing another pipeline shutdown. Staff implemented best management practices by diverting the drainage, which has remained low and stable, to a nearby storm drainage system. The drainage is being dechlorinated, and SFPUC staff are regularly monitoring the site. Further evaluations will be undertaken for this pipeline in the coming months.
f. Conditional blanket waiver approval for compliance with water main separation: In July 2021, the SFPUC received conditional approval from the State Water Resources Control Board (SWRCB) for compliance alternatives that were deemed to be equally protective of public health than the water main separation criteria in the California Waterworks Standards. This blanket waiver enables the SFPUC to implement a set of approved compliance alternatives when dealing with existing non-potable utility crossings in the Regional Water System. In the past, scenarios that did not meet the criteria would have required individual proposals to be submitted to SWRCB for approval. The approval process involved staff resources, SWRCB staff’s review time, and potential delays and change orders for SFPUC’s projects in construction. The blanket waiver will improve efficiency and reduce project risks for SFPUC pipeline projects in the future.
2. Construction
a. San Andreas Pipeline No. 2 (SAPL2): SAPL2 was previously inspected in 2015 after a main break disrupted water delivery to the City of San Bruno. Four segments of SAPL2 in San Bruno had deteriorated with severe pitting and corrosion. This project replaced the four segments (approximately 6,500 linear feet) of 54-inch
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diameter pipe. The construction work was awarded to Ranger Pipelines for $32 million dollars in January 2019. Construction reached final completion in April 2021. This project was closed out in December 2021; no further updates will be provided in this report. b. Town of Sunol Potable and Raw Water Transmission Pipelines:
These pipelines conflict with Alameda County Transportation Commission’s (ACTC) project to widen freeway I-680. SFPUC staff worked closely with ACTC staff to develop the design to replace segments of the 12-in potable and raw waterlines. In June 2021, ACTC started construction for their project, which includes installing new Town of Sunol pipelines crossing I-680. For this reporting period, minimal progress was made due to long procurement times for the steel pipe.
III. Pipeline Inspection Program
A. Local Water Facilities
In 2018, SFPUC implemented a pro-active leak detection pilot program to assess the effectiveness and benefits of installing acoustic based leak detection monitoring sensors procured from Echologics, a non-invasive acoustic technology for underground pipeline. The sound sensors proactively capture non-surfacing leaks and help the prevention of water loss as well as reduce the potential for property damage associated with catastrophic leaks.
The pilot program installed 160 monitoring devices within the Diamond Heights Neighborhood. In September 2020, the SFPUC expanded the monitoring and pilot program to include an additional 150 monitoring devices in the Bernal Heights and Portola neighborhoods.
For the current reporting period, one (1) new potential sub-surface leak was identified, while there are two (2) ongoing sub-surface leaks that need additional correlation. See Table 7 for a list of the sites that have been investigated and repaired. Map 3 identifies the locations that were investigated since the pilot began in 2018.
Table 7
Leak Sites Investigated and Repaired
No. Investigation
State Address
Field
Investigated
Date
Leak
Repair
Date
Leak
Type
1 Investigation
Pending
0-99 Block of
Newberg St
ongoing - -
2 Continued
Monitoring
100 Block of
Topaz Way.
ongoing - -
3 Continued
Monitoring
200 Block of
Justin Dr.
ongoing - -
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Map 3
B. Regional Water Facilities
Physical pipeline inspections were halted during the COVID-19 pandemic due to a lack of proper ventilation in confined spaces. During this reporting period however, the Water Supply and Treatment Division performed the following pipeline inspections using remotely operated tools:
1. San Antonio Pipeline, San Antonio Backup Pipeline, and Town of Sunol Potable Waterline Leak Detection: Ground fissures, 800 feet in length, had developed between three SFPUC pipelines and an active mining quarry (SMP- 30) operated by DeSilva Gates in Sunol Valley. To determine the cause of the ground fissures and support geotechnical investigation, leak detection inspections were performed for the three pipelines in August 2021.
The inspections were carried out using Pure Technologies’ Sahara acoustic leak detection tool (see Figure 2) for two of the pipelines. No leaks were found in the 60-inch San Antonio Pipeline or the 66-inch San Antonio Backup Pipeline. Pipe joints were inspected via closed circuit television and were found to be normal in appearance for the majority of the sections inspected.
The 12-inch Town of Sunol Potable Waterline was inspected using a leak correlator system. Again, no leaks were found. Pipeline leak was ruled out as a possible cause of the ground fissures.
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Figure 2
Pure Technologies’ Sahara Acoustic Leak Detection
IV. Summary of Pipeline Failures
A. Local Water Facilities
1. Main Break Data
82 distribution main breaks occurred during this reporting period. Of this total, 70 or 85.4% were due to natural pipeline breaks and twelve (12) or 14.6% were instigated by third-party contractors. Of the natural pipe failures, 68 or 97.1% occurred on cast iron pipes, and two (2) or 2.9% occurred on steel pipes. Table 8 identifies the number of breaks based on material type and decade installed .
Table 8
Natural Pipeline Failures FY 21/22 (Q1 & Q2)
Pipe
Material
Decade
Installed
No. Breaks Per Diameter (Inches) #
Breaks %
2 4 6 8 12 20 24
Cast
Iron 1890 - - 2 1 - - - 3 4.3%
1920 - 1 5 3 - - - 9 12.9%
1930 1 - 25 5 1 - - 32 45.7%
1940 - - 3 - 1 - - 4 5.7%
1950 - - 6 1 - - - 7 10%
1960 2 2 3 3 1 - - 11 15.7%
Other - - 1 1 - - - 2 2.9%
Steel
1860 - - - - - 1 - 1 1.4%
1940 - - - - - - 1 1 1.4%
Total 70 100%
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The number of miles of pipe installed varies year to year; therefore, the failures were normalized to facilitate pipe break data comparisons. The break data for this reporting period reveals that pipelines installed in the 1860’s experienced the highest main break rate with 23 breaks per 100 miles of pipe installed and pipelines installed in the 1930’s experienced the second highest break rate at 13 breaks per 100 miles of pipe installed. Pipelines installed in other decades experienced 11 breaks or less per 100 miles of pipe installed, which is more than a 50% decrease from the 1860’s. See Table 9 displaying the number of breaks per mile of pipe by decade of pipe installation for this reporting period.
Table 9
FY 22 Q1 & Q2 Nominalized Pipeline Failures
2. Main Break Repair Expenses
Two (2) conventional repair methods were employed for most main breaks including: a) Installing a clamp to conceal and encompass the rupture or leak and b) Replacing the affected pipe section.
For this reporting period, 33 breaks have been repaired with clamps and 36 have been repaired by replacing a section of the affected pipe. One (1) main break that occurred along the 20-inch main at the Fillmore Street bridge was not repaired. Instead, the 20-inch main has been taken temporarily off-line to be carefully evaluated and assessed. The expenses incurred for the remaining 69 main breaks have been evaluated, calculated and summarized in Table 10.
Table 10
Estimated Main Break Repair Costs FY 22 Q1 & Q2
Repair Type Labor Material Paving Cost Per
Repair
Total
No.
breaks
Total
Repair
Cost
Clamp $314,200 $8,400 $45,500 $11,200 33 $368,100
Pipe
Replacement
$347,700 $11,900 $156,000 $14,300 36 $515,600
Total $883,700
23 4
2 9
13 6
8 11
2 0
5 10
15 20
25 1860 1890 1900 1920 1930 1940 1950 1960 1980
No. Breaks per Mile of Pipe
Decade
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The total cost of the main breaks during this reporting period is $883,700, which is $78,000 higher than the total main break repair cost of $805,700 for the previous 6-month reporting period. The main break costs, broken down by break type for the last two (2) reporting periods, are summarized in Table 11.
Table 11
Main Break Repair Cost Comparison
Repair Type
FY 21
Q3 &Q4
FY 22
Q1 &Q2
Clamp $366,950 $368,100
Pipe
Replacement $438,750 $515,600
Total Cost $805,700 $883,700
During this reporting period, the total cost to repair water main breaks increased by $78,000 and has been attributed to the following factors:
1. An increase of three main breaks occurred during this reporting period.
2. The average cost of a single clamp repair increased by $2,250 from $8,950 to $11,200. Therefore, the total cost for clamp repairs increased by $1,115 this reporting period.
3. An increase of eleven pipe section repairs occurred during this reporting period. Therefore, the total cost for pipe replacement repairs increased by $76,900.
B. Regional Water Facilities
1. Three pipeline leaks occurred in the Regional Water System during this reporting period. The first leak was on BDPL4 in the same vicinity as two previous leaks in Redwood City.
The failure location was at the transition joint between PCCP and steel elbow (see Figure 3). SFPUC staff is monitoring and managing the leak, which has remained low and stable. The BDPL4 PCCP Repair Project will investigate the root cause of the leaks that have occurred in this stretch of the pipeline and determine next steps.
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Figure 3
BDPL4 Leak in September 2021
2. In November 2021, two leaks were reported on the Town of Sunol 12-inch raw waterline. The leaks occurred within the construction site of ACTC’s project to widen freeway I-680. The leaks, caused by corrosion, were repaired with leak clamps. To minimize point loads, ACTC has since installed steel plates over the 12-inch potable and raw waterlines. Corroded sections of the 12-inch raw waterline will be replaced at the end of ACTC’s project.
V. Summary
The City Distribution, Water Supply and Treatment, and Water Quality Division performed numerous noteworthy and substantial maintenance and construction activities to linear assets during the period of June 30, 2021 through December 31, 2021. The Divisions will continue to research and utilize innovative technologies and practices that will provide continued maintenance enhancements while identifying solutions to reduce costs and keep in line with budget constraints.