CITY OF MANHATTAN BEACH 2025 TRIENNIAL PUBLIC HEALTH GOAL REPORT

Background

Provisions of the California Health and Safety Code (HSC §116470(b)) specify that water utilities with greater than 10,000 service connections prepare a special Public Health Goal Report (Report) every three years if water quality measurements have exceeded any Public Health Goal (PHG); the latest Report is due by July 1, 2022. PHGs are non‐enforceable goals established by the California Environmental Protection Agency (Cal‐EPA) and the Office of Environmental Health Hazard Assessment (OEHAA). The regulation also requires that where OEHHA has not adopted a PHG for a constituent, the water suppliers are to use the Maximum Contaminant Level Goal (MCLG) adopted by the United States Environmental Protection Agency (U.S. EPA). Only constituents having a California primary drinking water standard, also known as a Maximum Contaminant Level (MCL), and either a PHG or MCLG are required to be addressed in the Report. The attached table contains a list of all relevant current PHGs, MCLGs, MCLs, and Detection Limits for purposes of Reporting (DLRs).

A few constituents are routinely detected in water systems at levels usually well below the drinking water standards for which OEHHA or U.S. EPA has not yet adopted a PHG or MCLG. As PHGs and MCLGs are updated, the City will include them in its evaluation in future Reports as applicable.

The Report addresses any contaminants that, as of December 31, 2024, have Primary Drinking Water Standards (PDWS) set by California or U.S. EPA and have an equivalent PHG or a MCLG. This includes all chemical, microbiological and radiological constituents detected above the DLR in the City of Manhattan Beach's (City's) water supply between 2022 and 2024 at a level exceeding any applicable PHG or MCLG, as required by the regulation. The Report includes the numerical public health risk associated with the MCL and the PHG or MCLG, the type of risk to health that could be associated with each constituent, the best treatment technology available that could be used to reduce the constituent level, and an estimate of the cost to install that treatment if it is appropriate and feasible.

What are Public Health Goals (PHGs)?

PHGs are set by OEHHA and are based solely on public health risk considerations. None of the practical risk‐management factors that are considered by the U.S. EPA or State Water Resources Control Board (SWRCB) Division of Drinking Water (DDW) in setting MCL drinking water standards are considered in setting the PHGs. These factors include analytical detection capability, treatment technology available, benefits and costs. The PHGs are not enforceable and are not required to be met by any public water system. MCLGs are the federal equivalent to PHGs and likewise are non‐enforceable.

What Water Quality Data are Considered?

All water quality data collected in the City’s water system between 2022 and 2024 for purposes of determining compliance with drinking water standards was considered. This data was all summarized in our
2022, 2023, and 2024 Consumer Confidence Reports (CCRs) which were posted on the City’s website at Annual Water Quality Report. Copies are also available upon request by contacting the City’s Utilities Division at 310-802-5304. 

What Guidelines are Followed for this Report?

The Association of California Water Agencies (ACWA) formed a workgroup that prepared guidelines for water utilities to use in preparing these required reports. The ACWA guidelines were used in the preparation of the City’s report. No guidance was available from state regulatory agencies.

Best Available Treatment Technology and Cost Estimates:

Both the U.S. EPA and DDW adopt what are known as BATs or Best Available Technologies, which are the best-known methods of reducing contaminant levels to the MCL. Costs can be estimated for such technologies. However, since many PHGs and all MCLGs are set much lower than the MCL, it is not always possible, nor feasible to determine what treatment is needed to further reduce a constituent downward to or near the PHG or MCLG, many of which are set at zero. Estimating the costs to reduce a constituent to zero is difficult because it is not possible to verify by analytical means that the level has been lowered to zero. In some cases, installing treatment to try and further reduce very low levels of one constituent may adversely affect other aspects of water quality.

What Constituents were Detected that Exceed a PHG or MCLG?

Table 1 shows the constituents that were detected above the DLR that exceeded a PHG or MCLG. Following the table, there is a discussion of the constituents found in one or more of the City’s drinking water sources at levels above the PHG, or if no PHG, above the MCLG. It should be noted that potable water is purchased to supplement the City’s groundwater. The purchased water is from Metropolitan Water District (MWD) via a wholesaler (West Basin Municipal Water District).

Table 1

NOTES

Any data below the State’s DLR is considered non-detect (ND).
a Data represents the highest average detected during the reporting period (2022-2024). This column shows the source year of the data displayed.
b Bromate compliance is determined using the Running Annual Average (RAA). RAAs are calculated as the average of all samples collected within a 12-month period per site. The highest RAA is shown in Table 1.
c There is no MCL for lead; there is an Action Level (AL). Compliance is based on the 90th percentile lead result measured at customer taps.
d As a wholesaler, Metropolitan has no retail customers and is not required to collect samples at consumers' taps. MWD data shown are from treatment plant effluents.

ACRONYMS

AL: Action Level
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level Goal
ND: Non-Detect
NL: Notification Level
NS: Not Sampled
PHG: Public Health Goal

Arsenic

Arsenic is a metalloid with properties of both metal and nonmetal elements. It’s a natural component of Earth’s crust, but some forms of it are also used in manufacturing or industrial processes like wood preservatives, pesticides, automobile batteries, and semiconductors.

The MCL for Arsenic is 10 micrograms per liter (µg/L). California’s DLR is 2 µg/L and the PHG is 0.004 µg/L. Any data below the State’s DLR is considered ND. The Office of Environmental Health Hazard Assessment (OEHHA) has developed a Public Health Goal for arsenic in drinking water based on its carcinogenicity. The numerical health risk at the MCL is 2.5x10-3. This means 2.5 cancer cases per 1,000 population. The numerical health risk at the PHG is 1x10-6. This means one cancer case per 1,000,000 population. 

Manhattan Beach is not required to test for arsenic on an annual basis. It is part of a list of inorganic compounds that are tested once every three years. The groundwater wells were sampled in 2023 and 2024 to satisfy the requirements, and both results were non-detect (ND) as shown in Table 1. Metropolitan Water District took samples during all three years. In 2022, a single result was detected above the DLR. The annual average was ND, but the range shows one result above the PHG at 2.4 µg/L. 

The BATs for treating arsenic are activated alumina, adsorption media, coagulation/filtration, ion exchange, oxidation/filtration, or reverse osmosis.

Bromate
Bromate is a byproduct of the disinfection process and occurs when bromide in the water reacts with the ozone disinfectant. Bromate consumed in drinking water in excess of the MCL over many years may cause an increased risk of cancer. Bromate is categorized as a haloacetic acid. 

The MCL or State drinking water standard for bromate is 10 µg/L. The PHG is 0.1 µg/L. California’s DLR is 1 µg/L. OEHHA has developed a Public Health Goal for bromate in drinking water, based on its carcinogenicity. The numerical health risk at the MCL is 1x10-4. This means one cancer cases per 10,000 population. The numerical health risk at the PHG is 1x10-6. This means one cancer case per 1,000,000 population. 

Manhattan Beach does not use ozone, therefore it is not required to test for bromate. From 2022 through 2024, purchased water from MWD used to supplement the City’s groundwater had detections of bromate. The highest running annual average (RAA) was 7.6 µg/L in 2023, which was below the MCL (Table 1). 

Because bromate is a disinfection byproduct, the BAT for bromate involves control of the ozone treatment process to reduce its production.

Gross Alpha
There are radioactive materials naturally present in the Earth’s crust. Over billions of years, these materials can change form and create decay products. During this change process, energy is released. Gross alpha radiation is one form of the released, and that is why it can be found in drinking water.

The drinking water MCL for gross alpha is 15 picoCuries per liter (pCi/L). Because gross alpha is associated with a group of radionuclides rather than a single constituent, OEHHA concluded that a PHG was not practical. Gross alpha is carcinogenic, so the MCLG set by the U.S. EPA is 0 pCi/L. California’s DLR is 3 pCi/L. The numerical health risk at the MCL is 1x10-3. This means one cancer case per 1,000 population. The numerical health risk at the MCLG is 0.

Manhattan Beach is not required to test for radionuclides on an annual basis. As shown in Table 1, the groundwater wells were sampled in 2023 and 2024 to satisfy the requirements, and both results were ND. Metropolitan Water District was required to sample quarterly during 2023. The average was ND, but there were detections of gross alpha above the MCLG of 0 pCi/L. Results ranged from ND to 5 pCi/L, ultimately falling below the MCL.

The BAT for removal of gross alpha is reverse osmosis (RO). 

Gross Beta
The radioactive materials naturally present in Earth’s crust can decay over time. Beta particles are a type of radiation released as this decay process occurs. Gross beta can be naturally-occurring, but it can also come from man-made sources. 

The drinking water MCL for gross beta is 50 picoCuries per liter (pCi/L). Similar to gross alpha, gross beta is also associated with a group of radionuclides rather than a single constituent, so OEHHA did not establish a PHG. Gross beta is a carcinogen, so the MCLG set by the U.S. EPA is 0 pCi/L. California’s DLR is 4 pCi/L. The numerical health risk at the MCL is 2x10-3. This means two cancer cases per 1,000 population. The numerical health risk at the MCLG is 0. 

Manhattan Beach follows requirements stated in Section 64442, Title 22, California Code of Regulations and is not currently required to test for gross beta. MWD samples quarterly for Gross Beta. The highest results were from 2022. Results of the purchased water had detections of gross beta above the MCLG as shown in Table 1. Gross beta levels ranging from ND to 9.0 pCi/L were detected in the drinking water which exceed the MCLG but fall well under the MCL.

The BAT for removal of gross beta is reverse osmosis (RO) and ion exchange (IX).

Lead
Lead is a heavy metal that can originate from the internal corrosion of household water plumbing systems. Lead can also potentially come from industrial manufacturer discharges. It enters drinking water primarily through the leaching of lead-containing materials in household plumbing such as lead-based solder used to join copper pipes, brass and/or chrome-plated brass faucets, lead pipe connections from homes to water mains, and brass/bronze meters and valves.

There is no MCL for lead. Instead, taps in homes that are at higher risk for lead exposure are targeted for sampling every three years. The 90th percentile value from this sampling cannot exceed the Action Level (AL) of 15 µg/L. The most recent sampling at customers taps was in 2022. Two of the thirty-three samples exceeded the AL, but the 90th percentile value was 4.4 µg/L as shown in Table 1. Lead levels from MWD’s imported water and the levels of lead in the City’s groundwater wells were all ND during the reporting period.

OEHHA has developed a Public Health Goal for bromate in drinking water, based on its developmental Neurotoxicity, cardiovascular toxicity, and carcinogenicity. The numerical health risk at the AL is 2x10-6. This means two cancer cases per 1,000,000 people. The numerical health risk at the PHG is less than 1x10-6. This means one cancer case per 1,000,000 population.

The BAT for lead removal is optimal corrosion control and pH adjustment. Although not classified as a BAT, it’s also important to identify and replace lead service lines.

Uranium
Uranium is a naturally occurring radioactive element present in the earth’s crust. Uranium is found in both groundwater and surface water due to its natural occurrence in geological formations.

The drinking water MCL for uranium is 20 picoCuries per liter (pCi/L). The PHG is 0.43 pCi/L. California’s DLR is 1 pCi/L. Any data below the State’s DLR is considered ND. OEHHA developed a PHG in drinking water based on its carcinogenicity and kidney toxicity. The numerical health risk at the MCL is 5x10-5. This means five cancer cases per 100,000 population. The numerical health risk at the PHG is 1x10-6. This means one cancer case per 1,000,000 population.

Manhattan Beach is not required to test the groundwater for radionuclides on an annual basis. Table 1 shows there was a single result from within the 2022-2024 time period, and it was ND. MWD was required to sample quarterly during 2023. The annual average was 1.0 pCi/L with a range of ND to 3 pCi/L. All results fell below the MCL, but there were detections of gross alpha above the MCLG of 0 pCi/L.

The BAT for uranium removal includes reverse osmosis (RO), ion exchange (IX), lime softening, and coagulation/filtration.

Estimated Costs

Accurate cost estimates are difficult, if not impossible, and are highly speculative and theoretical. Levels of the constituents listed above are already below the MCLs. Furthermore, all but one of the detections above PHGs and MCLGs come from the purchased water, not the City’s groundwater. Therefore, the City’s opinion is that cost calculations are not required. It should be noted that MWD’s potable water meets all State of California, DDW and U.S. EPA drinking water standards set to protect public health.

Recommendations for Further Action

The Manhattan Beach drinking water quality meets all State of California, DDW and U.S. EPA drinking water standards set to protect public health. To further reduce the levels of the constituents identified in this report that are already significantly below the health-based MCLs established to provide safe drinking water, additional costly treatment processes would be required. The effectiveness of the treatment processes to provide any significant reductions in constituent levels at these already low values is uncertain. The health protection benefits of these further hypothetical reductions are not at all clear and may not be quantifiable. Additionally, because the constituents are present in the purchased drinking water, actions taken by the City may have little to no effect. Therefore, no action is proposed.

References:

California Health & Safety Code: Section 116470
California Code of Regulations. Title 22. Section 64442
California State Water Resources Control Board. Drinking Water Section. Hexavalent Chromium 
Office of Environmental Health Hazard Assessment: Public Health Goals 
United States Environmental Protection Agency: National Primary Drinking Water Regulations 

Attachments

1.  Table of Regulated Constituents with MCLs, PHGs or MCLGs
2.  Health Risk Information for Public Health Goal Exceedance Reports