Water Quality
The Los Angeles Department of Water and Power tested for more than 240 substances in its water supply in 2024, running over 102,500 individual tests and complying with every primary health-based drinking water standard. For San Fernando Valley homeowners, three measured parameters deserve attention beyond simple regulatory compliance. Hardness: LADWP's own data shows the San Fernando Valley and Western Los Angeles average 147 mg/L as calcium carbonate (8.6 grains per gallon), with individual zones reaching 275 mg/L, well into the "very hard" category by USGS classification. Arsenic: LADWP's 2024 report noted the highest detected level at 8.4 ppb, below the 10 ppb MCL but above the 5 ppb threshold that triggers public notification. PFAS: LADWP began monitoring for PFAS compounds in 2013 and has detected them in some source wells, though reported readings from blended distribution water remain below California and federal action levels. This article compiles those findings from LADWP's public reports, the California State Water Board, and EPA regulatory records.
Want to know what your specific home's water contains?
UpTown Cares has served 2,000+ families across the San Fernando Valley since 2022. A free in-home water test takes about an hour at your kitchen counter and gives you a reading for hardness, pH, chloramine, and other key parameters.
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LADWP serves approximately 3.9 million people across the city, including the bulk of the San Fernando Valley. The utility blends water from three main sources: the Los Angeles Aqueduct (fed by Sierra Nevada snowmelt via Owens Valley), Metropolitan Water District imports (sourced from the Colorado River and the State Water Project), and treated local groundwater pumped from the SFV alluvial basin. Each source arrives with a different contaminant profile. Aqueduct water tends to be softer and lower in total dissolved solids. MWD Colorado River imports carry higher mineral loads. Local groundwater brings the legacy of decades of industrial activity in the Valley. What comes out of your tap is a blend whose composition shifts with seasons, drought conditions, and groundwater availability. The SFV utility water quality comparison documents how source proportions affect what Valley customers receive month to month.
What the 2024 LADWP data shows for San Fernando Valley homes
LADWP's 2024 Drinking Water Quality Report, published by the California State Water Resources Control Board requirement, shows compliance across all primary standards. The table below summarizes the parameters of greatest practical interest for Valley homeowners, drawn from LADWP's public data and the California and federal regulatory frameworks that govern them. Verify current readings at LADWP's Drinking Water Quality Report page.
| Parameter | Detected (SFV / LADWP system) | CA or Federal Limit (MCL) | Source |
|---|---|---|---|
| Hardness | Avg. 147 mg/L (8.6 gpg); range 93 to 275 mg/L in SFV/Western LA | No federal MCL. USGS defines "hard" at 121 to 180 mg/L, "very hard" above 180 mg/L. | LADWP Water Quality FAQs (2022 data) |
| Arsenic | Highest detected: 8.4 ppb (2024); below MCL but above 5 ppb notification threshold | 10 ppb (CA and federal MCL) | LADWP 2024 DWQR |
| PFAS (PFOA) | Detected in some source wells; blended system water reported below action levels | 4 ppt (EPA MCL, effective April 2024) | LADWP Regulatory Compliance; EPA PFAS Rule |
| PFAS (PFOS) | Detected in some source wells; blended system water reported below action levels | 4 ppt (EPA MCL, effective April 2024) | LADWP Regulatory Compliance; CA State Water Board PFAS |
| Perchlorate | Documented in SFV groundwater and Colorado River source water; utilities manage via well closure and treatment | 6 µg/L (CA MCL); federal rule pending | CA DTSC perchlorate page |
How we compiled this data
The contaminant readings in this article come from three categories of primary public sources. First, LADWP's annual Drinking Water Quality Report (DWQR), a regulatory document required by the California State Water Resources Control Board's Division of Drinking Water. The report covers each calendar year's monitoring results, using running annual averages and highest detected levels for each regulated substance. Second, LADWP's Water Quality FAQ page, which publishes hardness measurements by geographic service area, updated from the utility's monitoring program. Third, federal EPA databases, including the agency's PFAS regulatory records and the Superfund site profiles for groundwater contamination in the greater San Fernando Valley.
This article does not include any LADWP contaminant data that the utility has not itself published. Where a number appears in this article, the source is linked. Where no verified number is available, no number is stated. For the most current readings, LADWP publishes updated annual reports at ladwp.com/drinking-water-quality-report and takes questions at the Water Quality Hotline, (213) 367-3182.
Water hardness in the San Fernando Valley
Hard water is the most common water quality complaint from homeowners across the San Fernando Valley, and the data explains why. LADWP's hardness measurements for the San Fernando Valley and Western Los Angeles show an average of 8.6 grains per gallon (147 mg/L as calcium carbonate), with a range of 5.4 to 16.1 grains per gallon (93 to 275 mg/L), depending on which source blend reaches a given neighborhood at a given time. LADWP classifies water above 7 grains per gallon as hard. The USGS water hardness scale defines "very hard" as anything above approximately 180 mg/L. The upper end of LADWP's SFV range, 275 mg/L, sits well into that very hard category.
The practical effects are visible in most Valley homes: white mineral deposits on faucets and showerheads, spotting on glass and car surfaces after washing, scale buildup inside water heaters that reduces their efficiency, and skin and hair dryness that many residents attribute to their water. These are aesthetic and appliance-life concerns rather than health concerns. The minerals responsible, primarily calcium and magnesium carbonates, are not harmful to drink. The question for homeowners is whether the scale damage and cleaning costs of hard water justify treatment. The SFV hard water and TDS explainer covers the full range of hardness consequences and the options that address them.
Hard water is costing Valley homeowners in appliance wear and cleaning time
UpTown Cares installs whole-house filtration systems across North Hollywood, Sherman Oaks, Encino, Northridge, and the broader San Fernando Valley. Every system comes with a lifetime warranty on workmanship and 0% APR financing.
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Arsenic detected below the legal limit but above the notification threshold
LADWP's 2024 Drinking Water Quality Report documented the highest detected arsenic level at 8.4 ppb, below California's and the EPA's 10 ppb maximum contaminant level. California state regulation requires water systems to notify customers when arsenic is detected above 5 ppb, even if it remains below the 10 ppb MCL. The 8.4 ppb reading triggers that notification requirement. LADWP is in compliance, and the 2024 report includes the required disclosure language for customers in the affected service area.
The context matters: the MCL of 10 ppb was set by the EPA in 2001 after years of debate over feasibility and cost. California's own public health goal for arsenic, set by the Office of Environmental Health Hazard Assessment (OEHHA), is 0.004 ppb, more than 2,000 times lower than the enforceable limit. The gap between the legal limit and the health-protective level is large. OEHHA's PHG reflects what scientists consider the level at which cancer risk is negligible over a lifetime of exposure. The MCL reflects what is achievable across all water systems at reasonable cost. Residents who want to minimize arsenic exposure below the MCL can do so with a point-of-use reverse osmosis system certified to NSF/ANSI Standard 58, which covers arsenic reduction. For a full analysis of the arsenic regulatory picture in the SFV, see the SFV arsenic article.
PFAS compounds in SFV source wells and the EPA's 2024 rule
LADWP has monitored its groundwater sources for PFAS since 2013, well before the EPA established formal monitoring requirements. The utility's regulatory compliance disclosure states that PFAS were detected in samples from some individual wells but that extracted groundwater is blended with water from other wells and with large volumes of surface water before entering the distribution system. LADWP has reported that its blended finished water has not exceeded California's response levels of 10 parts per trillion for PFOA and 40 parts per trillion for PFOS that were in effect through 2023.
In April 2024, the EPA finalized the first federal drinking water limits for PFAS compounds under the Safe Drinking Water Act. The new rule sets MCLs of 4 ppt for both PFOA and PFOS individually, 10 ppt for PFNA and PFHxS individually, and a combined limit for mixtures. Water systems have five years to comply. California's State Water Board maintains a dedicated PFAS monitoring and compliance program at waterboards.ca.gov/pfas that tracks detections and regulatory status for every public water system in the state. The broader picture of PFAS contamination in the SFV and Santa Clarita Valley, where some smaller water providers have faced more acute PFAS challenges, is covered in the PFAS and SFV water article. The EPA's Superfund cleanup program for legacy industrial groundwater contamination in the Valley, which includes PFAS and solvent plumes across four designated sites, is tracked at the EPA's SFV Area 2 Superfund site profile.
What this means for homeowners in the service area
San Fernando Valley tap water is legal and safe to drink as delivered by LADWP. The data shows a utility running a well-managed system and complying with every applicable standard. At the same time, the data also shows that compliance with the legal standard is not the same as absence of any contaminant, and in some cases (arsenic, arsenic PHG gap; PFAS new federal MCL) the regulatory goalpost recently moved or is moving. For homeowners who want to address what the utility's own data shows, the options are well-defined. A certified reverse osmosis system at the drinking tap addresses arsenic, PFAS, perchlorate, and nitrates simultaneously. A whole-house softening or conditioning system addresses hardness and scale. Combining both gives full-spectrum treatment at the point of use and the point of entry. UpTown Cares, in partnership with the Peggy Beatrice Foundation, installs AlkaVida systems across the San Fernando Valley, typically in 2 to 4 hours with no disruption to daily water service.
Last updated: August 24, 2026. For the most current LADWP monitoring data, visit ladwp.com/drinking-water-quality-report or call the Water Quality Hotline at (213) 367-3182.
What contaminants are in San Fernando Valley tap water?
LADWP's 2024 Drinking Water Quality Report shows the utility tested for more than 240 substances and complied with all primary health-based standards. Parameters detected at levels worth noting for Valley homeowners include hardness (average 147 mg/L), arsenic (highest detected 8.4 ppb, below the 10 ppb MCL), and PFAS compounds in some source wells (below California action levels in blended finished water). Perchlorate is also monitored and managed in SFV groundwater sources.
Is San Fernando Valley tap water safe to drink?
Yes. LADWP complied with every primary drinking water standard set by California and the EPA in 2024. "Safe by regulatory standard" and "free of all contaminants" are different things. The utility's own published data shows low levels of arsenic, hardness minerals, and PFAS in some source wells. Homeowners who want to reduce exposure below regulatory limits can use NSF-certified point-of-use filtration.
How hard is tap water in Sherman Oaks, Encino, and Northridge?
LADWP data shows the San Fernando Valley and Western Los Angeles average 8.6 grains per gallon (147 mg/L as calcium carbonate), with a range of 5.4 to 16.1 grains per gallon (93 to 275 mg/L). On LADWP's own hardness scale, anything above 7 grains per gallon is classified as hard. Most Valley neighborhoods fall in the hard to very hard range, which is why scale buildup on fixtures and appliances is a common homeowner complaint.
Does PFAS contamination affect San Fernando Valley drinking water?
LADWP has monitored for PFAS since 2013 and has detected compounds in some source wells. The utility reports that blended finished water has remained below California's action levels and below the new EPA MCLs of 4 ppt for PFOA and PFOS that took effect in April 2024. Water systems have five years to achieve full compliance. The California State Water Board publishes current detection data for all public water systems at waterboards.ca.gov/pfas.
What is the arsenic level in Los Angeles tap water?
LADWP's 2024 Drinking Water Quality Report documented the highest detected arsenic level at 8.4 ppb. The California and federal MCL is 10 ppb. California regulation requires public notification when arsenic exceeds 5 ppb even below the MCL, so LADWP discloses this finding in its annual report. The California OEHHA public health goal for arsenic is 0.004 ppb, far below the enforceable MCL, reflecting a large gap between what is legal and what scientists consider health-protective.
What water filter removes contaminants found in SFV tap water?
A reverse osmosis system certified to NSF/ANSI Standard 58 addresses the key contaminants documented in LADWP monitoring data: arsenic, PFAS, perchlorate, nitrates, and total dissolved solids. A whole-house carbon filtration system reduces chloramine taste and some organic compounds but does not reliably reduce hardness minerals, arsenic, or PFAS. Combining a whole-house system with a point-of-use reverse osmosis system at the kitchen tap gives comprehensive coverage for both aesthetic and health-relevant parameters.
