Is Downey, CA Tap Water Safe to Drink?
Downey tap water is legally compliant, but one contaminant exceeds health guidelines. Specifically: PFAS above EPA limits (PFOA: 11.09 ppt, PFOS: 26.2 ppt — limit is 4 ppt each). A point-of-use filter is recommended for drinking and cooking water. Downey also has very hard water at 190 PPM.
Hardness Scale: Where Downey Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Downey Compares
Downey's water is 38% harder than the national average of 138 PPM. It ranks #344 out of 1000 cities in our database (harder than 66% of US cities we track). Within California, it ranks #45 of 87 cities (6% above the state average of 180 PPM). Among mid-size cities (100k-200k), Downey ranks #76 of 189 for hardness. At this hardness level, water heaters run an estimated 35% less efficiently due to scale insulation, and major water-using appliances typically last 3 years less than the national average lifespan.
What Downey's Water Means for Your Home
Hardness: 190 PPM - Treatment Recommended
Downey has some seriously hard water. At 190 PPM (11.1 grains per gallon), your tap is loaded with dissolved calcium and magnesium picked up from underground limestone and dolomite formations. Here's the thing: it's perfectly safe to drink. The minerals won't hurt you. But they will hurt your wallet. That adds up. Hard water at 190 PPM increases household costs through scale-coated water heaters that use more energy, extra soap and detergent, and appliances that wear out faster. Most Downey homeowners don't realize it until the plumber shows up. That's 6% harder than the California average.
Contaminants & Safety
Forever chemicals (PFAS) are a serious concern here. Downey has PFOA at 11.09 ppt and PFOS at 26.2 ppt — the EPA's 2024 limit is 4 ppt for PFOA and PFOS individually. PFAS don't break down in your body or the environment. Research links long-term exposure to increased cancer risk, thyroid issues, and immune system problems. The fix: a whole-house activated carbon filter or a point-of-use reverse osmosis system. Look for NSF P473 certification — that's the standard that specifically tests for PFAS removal.
What's in the Treatment Process
Chromium-6 is naturally present in Downey's aquifer geology at 0.276 ppb — 14x the EWG health guideline. There's no federal legal limit for chromium-6 specifically (only total chromium), which is why EWG tracks it separately. All measurements are within federal legal limits. The EWG guidelines represent a more conservative, health-based standard.
How Hard Water Affects Your Home
At 190 PPM, untreated hard water has measurable effects on household costs and appliance life:
- Water heater inefficiency: Scale insulation forces the heater to work harder (DOE estimates up to 22% more energy for heavily scaled units)
- Soap and detergent: Hard water reduces lathering, requiring significantly more product
- Appliance replacement: Water heaters, dishwashers, and washing machines fail 2-4 years earlier due to scale buildup
- Plumbing maintenance: Scale buildup in pipes reduces flow and requires more frequent service
Note: Impact varies by household size, water usage, and local energy costs. A home water test provides the most accurate assessment for your specific situation.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 190 PPM | < 60 PPM | No federal limit | ⚠ Very Hard |
| Total Dissolved Solids | 318 PPM | < 300 PPM | 500 PPM | ⚠ Elevated |
| PFAS (total) | 85.17 ppt | — | No total limit | Detected |
| ↳ PFOA | 11.09 ppt | 0 ppt | 4 ppt (2024) | ⚠ Exceeds |
| ↳ PFOS | 26.2 ppt | 0 ppt | 4 ppt (2024) | ⚠ Exceeds |
| Lead | 6 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ⚠ Elevated |
| Chlorine / Chloramine | 1.7 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 3.16 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Recommendations for Downey Homes
Our Top Picks for Downey (190 PPM)
Hard water at 190 PPM causes scale buildup, increased energy use, and premature appliance failure. A softener protects your plumbing and appliances.
Recommended Filter for Downey
PFAS exceed EPA limits (PFOA: 11.09 ppt, PFOS: 26.2 ppt — limit: 4 ppt each). A certified filter reduces these contaminants effectively.
Quick Fix for Chlorine: Shower Filter
At 1.7 mg/L chlorine, many Downey residents notice dry skin, brittle hair, and that "pool smell" in the shower. A shower filter installs in 5 minutes, no tools needed.
How to Test Your Water in Downey
With PFAS at 85.17 ppt in Downey's supply, confirming your home's specific levels is especially important. PFAS vary by neighborhood and can concentrate differently depending on your position in the distribution system.
Free option: Request City of Downey's annual Consumer Confidence Report for official city-level data.
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About Downey's Water Supply
Water Utility: City of Downey
Water Source: Groundwater, MWD (Groundwater)
Population Served: 108,816
Hardness: 190 PPM (11.1 grains per gallon)
Downey draws its drinking water from groundwater sources — Groundwater, MWD. Groundwater typically requires less treatment than surface water because the earth acts as a natural filter. The tradeoff: dissolved minerals from underground rock formations, which is why hardness is elevated here. Calcium and magnesium dissolve into the water as it moves through limestone and dolomite. The system serves 109,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request City of Downey's Consumer Confidence Report (CCR) or test your own tap.
ZIP Codes Covered by This Report
This water quality data applies to all areas served by City of Downey in Downey, CA, including ZIP codes:
90239, 90240, 90241, 90242, 90606, 90670, 90671, 90723
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Water Softener Sizing for Downey
At 190 PPM (11.1 GPG), here is how to size a softener for your Downey home. Multiply hardness in GPG (11.1) by daily water usage (roughly 50 gallons per person). A family of four uses about 200 gallons/day: 11.1 GPG × 200 gal = 2220 grains/day. Over a 7-day regeneration cycle, that is 15,540 grains - a 32,000-grain softener is the right fit for most Downey households.
Compare Downey to Other California Cities
Frequently Asked Questions About Downey Water
Is Downey tap water safe to drink?
Where does Downey's water come from?
Do I need a water softener in Downey?
How do I remove PFAS from Downey tap water?
What water filter is best for Downey?
Is Downey water safe for babies and infants?
Does Downey water damage tankless water heaters?
Do I need both a softener AND a filter in Downey?
Data sources: Lead and copper data from EPA Safe Drinking Water Act LCR reporting. Contaminant data from utility-reported testing results. PFAS data from EPA UCMR5 (2023–2025). Hardness from USGS and municipal reports. Data reflects system-level testing results and may not match your specific tap due to neighborhood plumbing, season, or recent utility changes. For your utility's latest results, request their Consumer Confidence Report (CCR). Our methodology. Last updated: 2026-02-24.
What Downey Homeowners Actually Buy
Prioritized for contaminant reduction for homes with 190 PPM water and PFAS above EPA limits.
Affiliate disclosure: we may earn a commission. Selection based on Downey's water data.