Is Redmond, WA Tap Water Safe to Drink?
Redmond tap water is legally compliant, but one contaminant exceeds health guidelines. Specifically: PFAS above EPA limits (PFOS: 5 ppt — limit is 4 ppt each). A point-of-use filter is recommended for drinking and cooking water.
Hardness Scale: Where Redmond Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Redmond Compares
Redmond's water is 82% softer than the national average of 138 PPM - ranking in the bottom 88% for hardness nationwide. Most homes here do not need a softener. Within Washington, it ranks #9 of 26 cities (24% below the state average of 33 PPM). Among mid-size cities (100k-200k), Redmond ranks #167 of 189 for hardness.
What Redmond's Water Means for Your Home
Hardness: 25 PPM - Low Concern
Redmond's water is slightly hard at 25 PPM. Most households won't notice any issues at this level. Scale buildup is minimal, and a water softener would be overkill. Redmond is softer than 88% of US cities. If you're thinking about water treatment, contaminant filtration is where to focus your money, not softening.
Contaminants & Safety
Forever chemicals (PFAS) are worth watching here. Redmond has PFOS at 5 ppt, exceeding the EPA's 2024 limit of 4 ppt per compound. PFAS are synthetic compounds that accumulate in your body over time. A certified carbon filter or reverse osmosis system with NSF P473 certification is the most effective protection. See the regulatory timeline.
What's in the Treatment Process
Redmond's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 25.3 ppb (32% of the legal limit, but 169x the EWG guideline) and HAA5 at 23.2 ppb (39% of the legal limit, but 232x the EWG guideline). These are within legal limits, but the EWG sets much tighter thresholds based on cancer-risk research. A whole-house activated carbon filter reduces both chlorine and byproducts.
Chromium-6 was detected at 0.0988 ppb, which is 4.9x the EWG health guideline. There's no separate federal limit for chromium-6, only total chromium. A reverse osmosis system is the most effective removal method. All measurements are within federal legal limits. The EWG guidelines represent a more conservative, health-based standard.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 25 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 45 PPM | < 300 PPM | 500 PPM | ✓ OK |
| PFAS (total) | 9.2 ppt | — | No total limit | Detected |
| ↳ PFOA | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| ↳ PFOS | 5 ppt | 0 ppt | 4 ppt (2024) | ⚠ Exceeds |
| Lead | 2 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ✓ Low |
| Chlorine / Chloramine | 0.9 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 0.707 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Recommended Filter for Redmond
PFAS exceed EPA limits (PFOS: 5 ppt — limit: 4 ppt each). A certified filter reduces these contaminants effectively.
How to Test Your Water in Redmond
With PFAS at 9.2 ppt in Redmond'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 Redmond Water's annual Consumer Confidence Report for official city-level data.
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About Redmond's Water Supply
Water Utility: City of Redmond Water
Water Source: Tolt River + wells (Surface Water)
Population Served: 163,335
Hardness: 25 PPM (1.5 grains per gallon)
Redmond's drinking water comes from surface sources — Tolt River + wells. Surface water requires more extensive treatment than groundwater, including coagulation, filtration, and disinfection. This heavier chlorination is why disinfection byproducts tend to be higher in surface-supplied systems. On the upside, surface sources often deliver softer water than deep aquifers. The system serves 163,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request City of Redmond Water'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 Redmond Water in Redmond, WA, including ZIP codes:
98052, 98053, 98072, 98073, 98077
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Redmond to Other Washington Cities
Frequently Asked Questions About Redmond Water
Is Redmond tap water safe to drink?
Where does Redmond's water come from?
Do I need a water softener in Redmond?
How do I remove PFAS from Redmond tap water?
What water filter is best for Redmond?
Is Redmond water safe for babies and infants?
What are disinfection byproducts in Redmond's water?
Is chromium-6 in Redmond's water?
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 Redmond Homeowners Actually Buy
Prioritized for contaminant reduction for homes with 25 PPM water and PFAS above EPA limits.
Affiliate disclosure: we may earn a commission. Selection based on Redmond's water data.