CITY OF SAN CLEMENTE
2025 PUBLIC HEALTH GOALS REPORT
JUNE 2025
$WWDFKPHQW
City of San Clemente 1 2025 PHGs Report
2025 Public Health Goals (PHGs) Report
City of San Clemente
1.0 Introduction
Under the Calderon-Sher Safe Drinking Water Act of 1996 public water systems in California serving greater than 10,000 service connections must prepare a report containing information on 1) detection of any contaminant in drinking water at a level exceeding a Public Health Goal (PHG), 2) estimate of costs to remove detected contaminants to below the PHG using Best Available Technology (BAT), and 3) health risks for each contaminant exceeding a PHG. This report must be made available to the public every three years. The initial PHGs Report was due on July 1, 1998, and subsequent reports are due every three years thereafter.
The 2025 PHGs Report has been prepared to address the requirements set forth in Section 116470 of the California Health and Safety Code. It is based on water quality analyses during calendar years 2022, 2023, and 2024 or, if certain analyses were not performed during those years, the most recent data is used. The 2025 PHGs Report has been designed to be as informative as possible, without unnecessary duplication of information contained in the Consumer Confidence Report (also known as Water Quality Report), which is provided to customers by July 1 of each year.
There are no regulations explaining requirements for the preparation of PHGs reports. A workgroup of the Association of California Water Agencies (ACWA) Water Quality Committee has prepared suggested guidelines for water utilities to use in preparing PHGs reports. The ACWA guidelines were used in the preparation of this 2025 PHGs Report. These guidelines include tables of cost estimates for BAT. The State of California (State) provides ACWA with numerical health risks and category of health risk information for contaminants with PHGs. This health risk information is appended to the ACWA guidelines.
2.0 California Drinking Water Regulatory Process
California Health and Safety Code Section 116365 requires the State to develop a PHG for every contaminant with a primary drinking water standard or for any contaminant the State is City of San Clemente 2 2025 PHGs Report
proposing to regulate with a primary drinking water standard. A PHG is the level of a contaminant in drinking water that poses no significant health risk if consumed for a lifetime.
The process of establishing a PHG is a risk assessment based strictly on human health considerations. PHGs are recommended targets and are not required to be met by any public water system.
The State office designated to develop PHGs is the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA). The PHG is then forwarded to the State Water Resources Control Board, Division of Drinking Water (DDW) for use in revising or developing a Maximum Contaminant Level (MCL) in drinking water. The MCL is the highest level of a contaminant that is allowed in drinking water. State MCLs cannot be less stringent than federal MCLs and must be as close as is technically and economically feasible to the PHGs. DDW is required to take treatment technologies and cost of compliance into account when setting an MCL. Each MCL is reviewed at least once every five years.
Two radiological contaminants (gross alpha particle activity and gross beta particle activity) have MCLs but do not yet have designated PHGs. For these contaminants, the Maximum Contaminant Level Goal (MCLG), the federal U.S. Environmental Protection Agency (USEPA) equivalent of PHGs, is used in the 2025 PHGs Report.
3.0 Identification of Contaminants
Section 116470(b)(1) of the Health and Safety Code requires public water systems serving more than 10,000 service connections to identify each contaminant detected in drinking water that exceeded the applicable PHG. Section 116470(f) requires the MCLG to be used for comparison if there is no applicable PHG.
The City of San Clemente (City) water system has approximately 17,587 service connections.
The following constituents were detected at one or more locations within the drinking water system at levels that exceeded the applicable PHGs or MCLGs:
x Arsenic – naturally-occurring in treated surface water purchased from Irvine Ranch Water District’s (IRWD) Baker Water Treatment Plant (BWTP).
City of San Clemente 3 2025 PHGs Report
x Bromate – formed when naturally-occurring bromide reacts with ozone during the disinfection process in treated surface water purchased from Metropolitan Water District of Southern California (MWDSC).
x Chlorite – byproduct of drinking water disinfection in treated surface water purchased from IRWD’s BWTP.
x Gross alpha particle activity (gross alpha) – naturally-occurring in treated surface water purchased from IRWD’s BWTP and from MWDSC.
x Gross beta particle activity (gross beta) – naturally-occurring in treated surface water purchased from IRWD’s BWTP and from MWDSC.
x Uranium – naturally-occurring in treated surface water purchased from IRWD’s BWTP and from MWDSC.
The accompanying table shows the applicable PHG or MCLG and MCL for each contaminant identified above. The table includes the maximum, minimum, and average concentrations of each contaminant in drinking water supplied by the City in calendar years 2022 through 2024.
4.0 Numerical Public Health Risks
Section 116470(b)(2) of the Health and Safety Code requires disclosure of the numerical public health risk, determined by OEHHA, associated with the MCLs, PHGs and MCLGs. Available numerical health risks developed by OEHHA for the contaminants identified above are shown on the accompany table. Only numerical risks associated with cancer-causing chemicals have been quantified by OEHHA.
Arsenic – OEHHA has determined the health risk associated with the PHG is 1 excess case of cancer in a million people and the risk associated with the MCL is 2.5 excess cases of cancer in 1,000 people exposed over a 70-year lifetime.
Bromate – OEHHA has determined the health risk associated with the PHG is 1 excess case of cancer in a million people and the risk associated with the MCL is 1 excess case of cancer in 10,000 people exposed over a 70-year lifetime.
City of San Clemente 4 2025 PHGs Report
Chlorite – OEHHA has not established a numerical health risk for chlorite because PHGs for non-carcinogenic chemicals in drinking water are set at a concentration at which no known or anticipated adverse health risks will occur, with an adequate margin of safety.
Gross Alpha – OEHHA has not established a PHG. USEPA has established an MCLG of 0.
USEPA has determined the risk associated with the MCL is 1 excess case of cancer in 1,000 people exposed over a 70-year lifetime for the most potent alpha emitter.
Gross Beta – OEHHA has not established a PHG. USEPA has established an MCLG of 0.
USEPA has determined the risk associated with the MCL is 2 excess cases of cancer in 1,000 people exposed over a 70-year lifetime for the most potent beta emitter.
Uranium – OEHHA has determined the health risk associated with the PHG is 1 excess case of cancer in a million people and the risk associated with the MCL is 5 excess cases of cancer in 100,000 people exposed over a 70-year lifetime.
5.0 Identification of Risk Categories
Section 116470(b)(3) of the Health and Safety Code requires identification of the category of risk to public health associated with exposure to the contaminant in drinking water, including a brief, plainly worded description of those terms. The risk categories and definitions for the contaminants identified above are shown on the accompanying table.
6.0 Description of Best Available Technology
Section 116470(b)(4) of the Health and Safety Code requires a description of the BAT, if any is available on a commercial basis, to remove or reduce the concentrations of the contaminants identified above. The BATs are shown on the accompanying table.
7.0 Costs of Using Best Available Technologies and Intended Actions Section 116470(b)(5) of the Health and Safety Code requires an estimate of the aggregate cost and cost per customer of utilizing the BATs identified to reduce the concentration of a contaminant to a level at or below the PHG or MCLG. In addition, Section 116470(b)(6) City of San Clemente 5 2025 PHGs Report
requires a brief description of any actions the water purveyor intends to take to reduce the concentration of the contaminant and the basis for that decision.
Arsenic – The BATs for removal of arsenic in water for large water systems are: activated alumina, coagulation/filtration, electrodialysis, ion exchange, lime softening, oxidation/filtration, and reverse osmosis. Arsenic was detected above the PHG in the treated surface water purchased from IRWD’s BWTP. The City is in compliance with the MCL for arsenic. The estimated cost to reduce arsenic levels in the treated surface water purchased from IRWD’s BWTP to below the PHG of 0.004 microgram per liter (μg/l) using ion exchange was calculated.
Because the DDW detection limit for purposes of reporting (DLR) for arsenic is 2 μg/l, treating arsenic to below the PHG level means treating arsenic to below the DLR of 2 μg/l. There are numerous factors that may influence the actual cost of reducing arsenic levels to the PHG.
Achieving the water quality goal for arsenic could be approximately $912,000 per year, or $52 per service connection per year.
Bromate – The BATs for removal of bromate in water for large water systems are:
coagulation/filtration optimization, granular activated carbon, and reverse osmosis. Bromate was detected above the PHG in the treated surface water purchased from MWDSC. The City is in compliance with the MCL for bromate. The estimated cost to reduce bromate levels in MWDSC water to below the PHG of 0.1 μg/l using reverse osmosis was calculated. Because the DLR for bromate is 1 μg/l, treating bromate to below the PHG level means treating bromate to below the DLR of 1 μg/l. There are numerous factors that may influence the actual cost of reducing bromate levels to the PHG. Achieving the water quality goal for bromate could range from approximately $1,960,000 to $16,800,000 per year, or between $111 and $953 per service connection per year.
Chlorite – As indicated above, chlorite is a byproduct of the drinking water disinfection process in the treated surface water purchased from IRWD’s BWTP. The BAT to reduce chlorite in drinking water is controlling the water treatment process to reduce the disinfectant demand and controlling the disinfection treatment process to reduce the disinfectant levels. The City is in compliance with the MCL for chlorite. IRWD is already optimizing the treatment/disinfection process at the BWTP. Therefore, the cost of reducing chlorite to the PHG level cannot be estimated.
City of San Clemente 6 2025 PHGs Report
Gross Alpha, Gross Beta, and Uranium – The only BAT for the removal of gross alpha in water for large water systems is reverse osmosis, which can also remove gross beta and uranium, if detected. Gross alpha and gross beta were detected above their respective MCLGs in the treated surface water purchased from IRWD’s BWTP and from MWDSC. Uranium was detected above the PHG in the treated surface water purchased from IRWD’s BWTP and from MWDSC. The cost of providing treatment using reverse osmosis to reduce gross alpha levels to the MCLG of 0 picoCurie per liter (pCi/l) (and consequently gross beta to below the MCLG of 0 pCi/l and uranium to below the PHG of 0.43 pCi/l) was calculated. Because the DLR for gross alpha is 3 pCi/l, treating gross alpha to 0 pCi/l means treating it to below the DLR of 3 pCi/l (and treating gross beta and uranium to below their respective DLRs of 4 pCi/l and 1 pCi/l).
Achieving the water quality goal for gross alpha could range from $2,310,000 to $19,800,000 per year, or between $132 and $1,130 per service connection per year.
All Contaminants – In addition, a cost estimate to treat all water produced by the City using reverse osmosis to remove all the contaminants detected above the PHGs or MCLGs was calculated. All the contaminants listed in the accompanying table may be removed to nondetectable levels by reverse osmosis. As shown on the accompanying table, achieving the water quality goals for all contaminants using reverse osmosis could range from $2,310,000 to $19,800,000 per year, or between $132 and $1,130 per service connection per year.
For additional information, please contact Utilities Manager Mr. Dustin Burnside at (949) 366-1553, or write to the City of San Clemente, Utilities Department, 380 Avenida Pico, Building N, San Clemente, California 92672.
J:\2351\017 - 2025 PHG\San Clemente 2025 PHG_text_Final.docx
UNITS PHG MCL DLR CATEGORY CANCER RISK CANCER BEST AGGREGATE COST PER
PARAMETER OF OR AVERAGE RANGE OF AT PHG RISK AVAILABLE COST SERVICE CONNECTION MEASUREMENT (MCLG)* RISK OR MCLG AT MCL TECHNOLOGIES PER YEAR PER YEAR INORGANIC CHEMICALSArsenic ȝg/l 0.004 10 2 ND ND - 2.3 C 1 x 10-6 2.5 x 10-3 AA,C/F,E,IE,LS,O/F,RO $912,000 (a) $52 (a) Bromate ȝg/l 0.1 10 1 ND ND - 6.3 C 1 x 10-6 1 x 10-4 C/F, GAC, RO $1,960,000 - $16,800,000 (b) $111 - $953 (b)Chlorite mg/l 0.05 1 0.02 0.02 ND - 0.13 H NA NA CT (c) (c) RADIOLOGICALGross Alpha Particle Activity pCi/l (0) 15 3 ND ND - 5.4 C 0 1 x 10-3 RO $2,310,000 - $19,800,000 (d) $132 - $1,130 (d) Gross Beta Particle Activity pCi/l (0) 50 4 4.3 4.6 - 9 C 0 2 x 10-3 IE, RO -- -- Uranium pCi/l 0.43 20 1 1.6 1.5 - 3 C 1 x 10-6 5 x 10-5 IE, RO, LS,C/F -- -- ALL CONTAMINANTS -- -- -- -- -- -- -- -- -- RO $2,310,000 - $19,800,000 (e) $132 - $1,130 (e) * MCLGs are shown in parentheses. MCLGs are provided only when no applicable PHG exists.
TREATMENT TECHNOLOGIESAA = Activated Aluminum
RISK CATEGORIES C/F = Coagulation/FiltrationC (Carcinogen) = A substance that is capable of producing cancer. CT = Control of treatment processes to reduce disinfectant demand andH (Hematotoxicity and Neurotoxicity) = Causes anemia and neurobehavioral effects control of disinfection treatment processes to reduce disinfectant levels E = Electrodialysis
NOTES GAC = Granular Activated CarbonDLR = Detection Limit for Purposes of Reporting IE = Ion ExchangeMCL = Maximum Contaminant Level LS = Lime SofteningMCLG = Maximum Contaminant Level Goal O/F = Oxidation/Filtrationȝg/l = micrograms per liter or parts per billion RO = Reverse Osmosis mg/l = milligrams per literNA = Not ApplicableND = Not DetectedpCi/l = picoCuries per literPHG = Public Health Goal (a) Estimated cost to remove arsenic using IE.(b) Estimated cost to remove bromate using RO.(c) Costs could not be estimated.(d) Estimated cost to remove gross alpha particle activity using RO, which also removes gross beta particle activity and uranium. (e) Assuming treating the entire production by RO, which can remove all contaminants listed in the above table to below the detectable levels. 2025 PUBLIC HEALTH GOALS REPORT
CITY OF SAN CLEMENTE
CONCENTRATION
J:\2351\017 - 2025 PHG\San Clemente_phgtable_2025.xlsx