Grand Coulee, WA Water Safety: 83/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-04
How does Grand Coulee tap water hold up under EPA scrutiny? Above average for WA — documented violations are uncommon and the safety grade reflects a clean overall record.
How Grand Coulee Compares
Data: EPA SDWIS Last verified: 2026-06-04
What You Should Know About Grand Coulee Water
- Average lead level: 0.0032 mg/L.
- Homes built before 1986: 77% — older plumbing may contain lead solder.
- Estimated remediation: $400 per household.
- CDC health risk index: 12.63 — above typical levels.
Who Supplies Your Water in Grand Coulee
Structurally, Grand Coulee, WA's water supply is divided. Federal data identifies 2 water systems in the area, with 2 providers serving the bulk of residential connections. These utilities operate independently, meaning rate-setting authority and EPA compliance accountability are distributed rather than centralized.
Overview
We track water quality and home safety data for 1 ZIP code in Grand Coulee, Washington, covering 2 community water systems serving approximately 1,341 people.
No EPA violations recorded across any ZIP codes in Grand Coulee — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Grand Coulee: B (83/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Grand Coulee water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0032 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 99133 | B | City of Grand Coulee Water Department | 1,428 |
All ZIP Codes in Grand Coulee
- 99133 [B]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Grand Coulee
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Housing & Infrastructure in Grand Coulee
With 77% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Lead solder was standard in copper plumbing until federally banned in 1986; lead pipes were common in service lines pre-1970. Grand Coulee's median build year of 1978 reflects a housing stock where these older materials are a pervasive feature — not a rare legacy — of the residential plumbing landscape.
Over half of homes in Grand Coulee were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Grand Coulee Homeowners
For most homeowners in Grand Coulee, the estimated cost of water and safety remediation represents a proportionally modest share of what properties are worth — placing this area in the lower tier of the remediation share scale.
Remediation costs in Grand Coulee are relatively low compared to home values. The $0–$800 estimated range is a small fraction of median property value. Home values are 53% below the Washington average.
Lead Exposure Risk for Children in Grand Coulee
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
When older housing represents 77% of the local inventory or aggregate readings approach the federal action level, an in-home check becomes the standard way to translate citywide averages into the specific reality of an individual Grand Coulee address.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Deep Dive Reports
Detailed analysis for Grand Coulee, WA