A
89

US Water Score: A

Downey, CA 90241

Los Angeles County · Population served: 110,556 · Data updated July 2026

Service-area evidence: EPA service-area records associate the listed system with this ZIP. Boundaries may still overlap or change.

Water Systems Serving This Area

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DOWNEY - CITY, WATER DEPT.
Groundwater · Pop. 110,556
PWSID: CA1910034
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GSWC - NORWALK
Surface water · Pop. 43,176
PWSID: CA1910098
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LIBERTY UTILITIES - MESA CREST
Surface water · Pop. 1,619
PWSID: CA1910241
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LIBERTY -YERMO
Groundwater · Pop. 861
PWSID: CA3610118
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LIBERTY-BELLVIEW HEIGHTS
Groundwater · Pop. 155
PWSID: CA3600010

Contaminants Detected

ContaminantDetected LevelEPA MCLHealth GuidelineStatus
Lead
1.8
15 ppb 1 ppb Warning

PFAS / Forever Chemicals

8 detected 2 above comparison value

UCMR5 occurrence results are screening information, not a finding of regulatory compliance or noncompliance. PFAS rules and compliance dates are evolving.

CompoundLevelEPA MCLHealth GuidelineStatus
PFOS44.0 ppt4 ppt4 pptAbove comparison value
PFPeA27.0 pptNo standardNo federal MCL shown
PFHxA21.0 pptNo standard400 pptNo federal MCL shown
PFOA15.0 ppt4 ppt4 pptAbove comparison value
PFBA10.0 pptNo standard500 pptNo federal MCL shown
PFBS8.9 ppt2000 ppt100 pptBelow comparison value
PFHxS8.9 ppt10 ppt10 pptBelow comparison value
PFHpA4.2 pptNo standardNo federal MCL shown

Water Quality Summary

Understanding Your Water in Downey

Tap water quality in Downey, California (90241) receives an overall grade of A (Lower record-based concern) with a score of 89 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is roughly in line with the California state average of 92. Compared to the national average (75), this area performs significantly better. The area is served by 5 water systems providing water to approximately 110,556 people, using groundwater and surface water sources. Testing has found elevated levels of Lead that warrant attention. Notably, 2 PFAS compounds exceed the EPA final MCL value used for comparison — a significant concern given the persistent nature of these chemicals. The area has a clean violation record over the past 5 years — a positive indicator of consistent water quality management.

Your Score 89/100 A
vs State 4 pts below California avg (92)
vs National 14 pts above national avg (75)

What a Grade A Means

A score of 89/100 means public water-system records for Downey, CA show relatively few concerns in the US Water Score model. This is an internal score, not an EPA safety rating, and it does not guarantee conditions at any specific tap.

Groundwater: drawn from underground aquifers via wells
Surface water: sourced from rivers, lakes, or reservoirs

Health Information

What These Contaminants Mean for You

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Lead in Your Water

Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.

Health Effects

Even low levels of lead exposure can cause developmental delays in children, kidney damage, and cardiovascular effects in adults. The EPA action level is 15 ppb, but health experts recommend no safe level of lead in drinking water.

Common Sources

Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.

What You Can Do

If lead is detected above 1 ppb, consider using a certified lead-removal filter (NSF/ANSI 53) for drinking and cooking water. Run cold water for 30 seconds before use if water has been sitting in pipes.

Common Questions

Frequently Asked Questions

Based on public water-system records, Downey, California receives an internal US Water Score grade of A (Lower record-based concern) with a score of 89/100. This indicates relatively few system-level concerns in our model, but it is not an EPA safety rating and does not guarantee tap conditions inside individual homes.

ZIP code 90241 is served by 5 water systems using groundwater, surface water sources, providing water to approximately 110,556 people. Multiple source types mean your water may come from a blend of surface and underground sources.

Lead was reported at 1.8 ppb in public-system records for Downey, California. This is below the currently applicable EPA action level of 15 ppb, but may be above more protective health guidance; EPA's future LCRI action level is 10 ppb. Household plumbing can materially change tap-level exposure, so consider certified filtration and individual tap testing, especially where children are present.

Yes — 8 PFAS compounds were detected in records associated with water serving Downey, California, and 2 results exceeded the numerical EPA MCL value used for comparison. UCMR5 occurrence results alone are not a regulatory compliance determination. PFAS rules and compliance timelines are evolving; verify current information with the utility and EPA.

Water systems serving Downey, California have zero violations in the last 5 years. This is a positive indicator of consistent regulatory compliance and water quality management.

Based on detected contaminants (lead, PFAS), residents in Downey, California should consider: Reverse osmosis (RO) system — most effective for PFAS, lead, and other contaminants. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.

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