Is Coulee City, WA Tap Water Safe to Drink?
Graded A, with 2 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
90.4/100
waterverge.com Coulee City, WA — Water Quality Report
Coulee City's drinking water received a grade of A (90.4 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 944 residents using groundwater.
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 20 violations on record, including 6 health-based violations. 2 remain unresolved.
What to know about Coulee City's water
Coulee City ranks #39 out of 294 cities in Washington for water quality, placing it above average in the state.
Coulee City relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Coulee City may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 6 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Coulee City, WA water safe to drink?
Coulee City's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (90.4/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 944 residents using groundwater (wells).
Recent water quality updates for Coulee City
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Coulee City's water quality assessment. Grade: A (90.4/100).
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-4309). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3227). Coastal Storm event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Coulee City's water supply.
Well within EPA limits.
Violation history
Coulee City's water system has 20 total violations on record, including 6 health-based violations. 2 remain unresolved. 6 violations were issued in the last 5 years.
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.
Where does Coulee City's water come from?
Coulee City's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 944 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Coulee City residents can do
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 Coulee City compares by contaminant
Explore where Coulee City ranks among all Washington cities for specific contaminants.
Water source & infrastructure
Where Coulee City's water comes from
Coulee City's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 944 people through 1 water system.
Water systems serving Coulee City
| System Name | PWSID | Population | Source |
|---|---|---|---|
| COULEE CITY TOWN OF | WA5315300 | 944 | GW |
How Coulee City compares
Full Washington rankings →Coulee City's score of 90.4/100 is above the average of 53/100 among major Washington cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Washington rankings →About Coulee City, WA
Learn more about your water
Guides and resources related to Coulee City's water quality findings.
Explore water quality across Grant
Frequently asked questions
Is Coulee City, WA tap water safe to drink?
Coulee City's water quality earned a grade of A (90.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #39 out of 294 cities tested in Washington.
What contaminants are in Coulee City's water?
Lead was measured at 0.0 ppb (90th percentile). 20 violations are on record.
How is Coulee City'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 Coulee City?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Coulee City's water come from?
Coulee City's water is sourced from Groundwater. The city has 1 water system serving approximately 944 residents.
What health violations has Coulee City's water system had?
Coulee City has 6 health-based violations on record. The most recent violation was recorded in January 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Coulee City's groundwater at risk of contamination?
Coulee City 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 20 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 Coulee City's water compare to other cities?
Coulee City ranks #39 out of 294 cities in Washington (better than 87% of state cities) and #2252 out of 15744 cities nationally (86th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Coulee City's small water system affect quality?
Coulee City's system serves approximately 944 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 20 violations on record.