Seattle Drinking Water Quality
What's Really in Your Tap Water?
Good news for Seattle residents — your tap water meets all federal safety standards. At just 24.4 ppm (1.4 gpg), the water is pleasantly soft. Lead levels test well below the EPA action level. No violations have been recorded in the past 3 years.
Safe to Drink
Meets all EPA standards
1.4 GPG hardness
Lead
Below EPA action level
EPA action level: 15 ppb
Hardness
Soft water
US Average: 100 ppm
Is Seattle Tap Water Safe to Drink?
Seattle tap water meets all EPA health standards and is safe to drink.
8 contaminants were tested in Seattle's water. 6 were detected — all within EPA limits.
Disinfection Byproducts — Haloacetic Acids (HAA5) is at 33 ppb — 55% of the EPA limit (60 ppb). Within legal limits, but elevated.
A group of five chemicals that form as byproducts when chlorine or other disinfectants react with organic matter in water. Long-term exposure may increase the risk of cancer. Some studies link them to reproductive and developmental effects.
→ An activated carbon filter can reduce haloacetic acids in your drinking water.
Metals — 1 contaminant detected, all within EPA limits. Highest: Arsenic at 0.4 ppb (4% of EPA limit).
Inorganic Chemicals — 2 contaminants detected, all within EPA limits. Highest: Fluoride at 0.7 ppm (18% of EPA limit).
PFAS "Forever Chemicals" — No PFAS "forever chemicals" were detected in recent testing — a positive result.
The data below shows test results from 1 water utility serving 1.1M people in the Seattle area.
Do I Need a Water Filter?
Seattle tap water meets all EPA standards and is safe to drink without additional filtration. For extra peace of mind, a basic carbon filter can improve taste.
How Hard is Seattle Water?
24.4 ppm
1.4 grains per gallon
Soft water requires no treatment and is gentle on skin and appliances.
Estimated from 1 neighboring county. Actual values may vary.
Impact on Your Home
Shower
Great for skin & hair
Kitchen
No water spots
Laundry
Clothes stay soft
Appliances
No scale buildup
Regional Comparison
Values in ppm (mg/L as CaCO₃)
Range: 15–30 ppm
Based on 42 samples from SPU / Known regional data (2024)
Your pipes tell a different story
The data above shows what leaves the treatment plant—not what comes out of your faucet. Old pipes, lead solder, and building plumbing can add contaminants the city never tests for. Know exactly what's in your Seattle tap water.
Home test kits detect lead, bacteria, pesticides, and 100+ other contaminants. Results in 5-10 business days from certified labs.
Lead & Contaminants
Understanding lead levels and water quality violations in Seattle
Lead Test Results
90th Percentile Lead Level
3.5 ppb
Seattle lead levels are well within safe limits.
Regular testing is still recommended, as lead can enter water through household plumbing.
Last sampled: 2024-12-31
About Lead in Drinking Water
What is Lead in Water?
Lead is a toxic metal that can dissolve into drinking water from older pipes, solder, and fixtures. It's invisible, tasteless, and odorless, making testing the only way to detect it. The EPA has set an action level of 15 ppb, though they emphasize there is no safe level of lead exposure.
Potential Health Effects
Developmental delays, learning difficulties, lower IQ, behavioral issues
High blood pressure, kidney damage, reproductive issues
How to Reduce Exposure
- •Run water for 30 seconds to 2 minutes before drinking, especially in the morning
- •Use cold water for cooking and drinking (hot water dissolves more lead)
- •Install a NSF-certified filter designed to remove lead
- •Test your water, especially if your home was built before 1986
PFAS “Forever Chemicals”
No PFAS detected
PFAS are synthetic chemicals that don't break down in the environment. No PFAS were detected in the most recent testing.
Haloacetic Acids (HAA5)
55% of EPA limit
Range: 11–46 ppb
Total Trihalomethanes (TTHM)
54% of EPA limit
Range: 21–63 ppb
Chlorine
25% of EPA limit
Range: 0–2.2 ppm
Fluoride
18% of EPA limit
Range: 0.6–0.8 ppm
Other Detected Contaminants
8 contaminants detected
| Contaminant | Your Water | Limit (MCL) | Status |
|---|---|---|---|
Arsenic | 0.4 ppb Range: 0.2-0.6 Highest average (Cedar supply) | 10 ppb 0 | Safe 4% of limit |
Fluoride | 0.7 ppm Range: 0.6-0.8 Water additive | 4 ppm Goal: 4 ppm | Safe 18% of limit |
Nitrate | 0.08 ppm Tolt supply - Cedar was ND | 10 ppm Goal: 10 ppm | Safe 1% of limit |
Total Trihalomethanes (TTHM) | 43 ppb Range: 21-63 Highest average (Tolt supply) | 80 ppb | Caution 54% of limit |
Haloacetic Acids (HAA5) | 33 ppb Range: 11-46 Highest average (Tolt supply) | 60 ppb | Caution 55% of limit |
Chlorine | 1 ppm Range: 0-2.2 | 4 ppm | Safe 25% of limit |
PFOA | 0 ppt Range: 0-0 ND - UCMR5 - 0/8 samples detected | 4 ppt 0 | Safe |
PFOS | 0 ppt Range: 0-0 ND - UCMR5 - 0/8 samples detected | 4 ppt 0 | Safe |
MCL = Maximum Contaminant Level (EPA legal limit)
EPA Compliance History
Excellent Record
No violations in past 3 yearsThis utility has maintained full EPA compliance. No action needed, but regular home testing is still recommended.
3-Year Violation Summary
0
Total Violations
0
Health-Related
0
Administrative
Health-Related Violations
Contaminant exceeded EPA safety limits. May require filter or alternative water source.
Administrative Violations
Missed testing deadlines or reporting. Does not indicate water quality issues.
Who Provides Seattle's Water?
Utility Name
SEATTLE PUBLIC UTILITIES
EPA System ID (PWSID)
WA5377050
Primary Water Source
Surface Water
Population Served
1.1M
Frequently Asked Questions
Common questions about Seattle tap water quality
Nearby Cities in Washington
Tacoma
Vancouver City of
Soft water
Spokane City of
Soft water
Bellevue City of
Soft water
Everett Public Works Dept. City of
Soft water
Alderwood
Soft water
This data is for informational purposes only. Water quality can vary by neighborhood and building. For official reports, contact your local water utility or the EPA. Learn about our methodology
Data source: SPU / Known regional data (2024) • View report