Is Grand Coulee, WA Tap Water Safe to Drink?
Graded A-, with 3 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
89.2/100
waterverge.com Grand Coulee, WA — Water Quality Report
Grand Coulee's drinking water received a grade of A- (89.2 out of 100), indicating good water quality. The city's 2 water systems serve approximately 1,544 residents using purchased ground water.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 6 violations on record, including 1 health-based violation. 3 remain unresolved.
What to know about Grand Coulee's water
Grand Coulee ranks #51 out of 294 cities in Washington for water quality, placing it above average in the state.
Grand Coulee purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition.
As a small community water system, Grand Coulee may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Grand Coulee, WA water safe to drink?
Grand Coulee's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (89.2/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,544 residents using groundwater (wells).
Recent water quality updates for Grand Coulee
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Grand Coulee's water quality assessment. Grade: A- (89.2/100).
Federal disaster declaration (FEMA DR-4309). Flood event — may have impacted local water infrastructure.
Contaminants: Consumer Confidence Rule.
Federal disaster declaration (FEMA DR-3227). Coastal Storm event — may have impacted local water infrastructure.
Contaminants: Coliform (TCR).
Contaminants: Lead and Copper Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Grand Coulee's water supply.
Well within EPA limits.
Violation history
Grand Coulee's water system has 6 total violations on record, including 1 health-based violation. 3 remain unresolved.
Flood & environmental risk
Grant County has experienced 2 federally declared disasters since 2005. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Franklin Roosevelt Lake.
Where does Grand Coulee's water come from?
Grand Coulee's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 1,544 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Franklin Roosevelt Lake (lake).
What Grand Coulee residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Grand Coulee's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D1 — moderate droughtGrant County is currently in D1 (moderate drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Grant County has experienced 2 federally declared disasters since 2005. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Grand Coulee compares by contaminant
Explore where Grand Coulee ranks among all Washington cities for specific contaminants.
Water source & infrastructure
Where Grand Coulee's water comes from
Grand Coulee purchases its water supply from a regional wholesale provider rather than treating raw water directly.
Water quality depends on both the wholesaler's treatment standards and the condition of Grand Coulee's local distribution pipes and storage facilities.
Purchased water systems are common in suburban areas and smaller communities that lack the infrastructure for independent treatment.
The system is operated by local government ownership and serves approximately 1,544 people through 2 water systems.
Water bodies near Grand Coulee
Grand Coulee is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Grand Coulee
| System Name | PWSID | Population | Source |
|---|---|---|---|
| GRAND COULEE WATER DEPT CITY OF | WA5328700 | 1,428 | GWP |
| NORTH SHORE ACRES | WA5303370 | 116 | GW |
How Grand Coulee compares
Full Washington rankings →Grand Coulee's score of 89.2/100 is above the average of 53/100 among major Washington cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Washington rankings →About Grand Coulee, WA
Learn more about your water
Guides and resources related to Grand Coulee's water quality findings.
Explore water quality across Grant
Frequently asked questions
Is Grand Coulee, WA tap water safe to drink?
Grand Coulee's water quality earned a grade of A- (89.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #51 out of 294 cities tested in Washington.
What contaminants are in Grand Coulee's water?
Lead was measured at 0.0 ppb (90th percentile). 6 violations are on record.
How is Grand Coulee's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Grand Coulee?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Grand Coulee's water come from?
Grand Coulee's water is sourced from Purchased ground water. The city has 2 water systems serving approximately 1,544 residents.
What health violations has Grand Coulee's water system had?
Grand Coulee has 1 health-based violation on record. The most recent violation was recorded in July 2010. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 3 violations remain unresolved.
Is Grand Coulee's groundwater at risk of contamination?
Grand Coulee uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 6 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Grand Coulee's water compare to other cities?
Grand Coulee ranks #51 out of 294 cities in Washington (better than 83% of state cities) and #2979 out of 15744 cities nationally (81th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.