Is Coulee Dam, WA Tap Water Safe to Drink?
Graded A, with 1 unresolved violation on record. See what was cited — and what it means for your tap. What to do next ↓
90.7/100
waterverge.com Coulee Dam, WA — Water Quality Report
Coulee Dam's drinking water received a grade of A (90.7 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 1,359 residents using surface water.
Lead levels were measured at 1.7 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 3 violations on record, including 1 health-based violation. 1 remains unresolved.
What to know about Coulee Dam's water
Coulee Dam ranks #35 out of 294 cities in Washington for water quality, placing it above average in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
As a small community water system, Coulee Dam may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Coulee Dam, WA water safe to drink?
Coulee Dam's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (90.7/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,359 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Coulee Dam
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Coulee Dam's water quality assessment. Grade: A (90.7/100).
Federal disaster declaration (FEMA DR-4650). 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: Consumer Confidence Rule.
1 health-based. Contaminants: Surface Water Treatment Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Coulee Dam's water supply.
Well within EPA limits.
Violation history
Coulee Dam's water system has 3 total violations on record, including 1 health-based violation. 1 remain unresolved.
Flood & environmental risk
Okanogan County has experienced 4 federally declared disasters since 1972. 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 Coulee Dam's water come from?
Coulee Dam's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 1 water system serving approximately 1,359 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Franklin Roosevelt Lake (lake).
What Coulee Dam 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.
Coulee Dam's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
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 droughtOkanogan 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
Okanogan County has experienced 4 federally declared disasters since 1972. 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. | 1.7 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Coulee Dam compares by contaminant
Explore where Coulee Dam ranks among all Washington cities for specific contaminants.
Water source & infrastructure
Where Coulee Dam's water comes from
Coulee Dam's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 1,359 people through 1 water system.
Water bodies near Coulee Dam
Coulee Dam is located near 1 notable water body. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Coulee Dam
| System Name | PWSID | Population | Source |
|---|---|---|---|
| COULEE DAM WATER DEPT | WA5315400 | 1,359 | SW |
How Coulee Dam compares
Full Washington rankings →Coulee Dam's score of 90.7/100 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 Dam, WA
Learn more about your water
Guides and resources related to Coulee Dam's water quality findings.
Explore water quality across Okanogan
Frequently asked questions
Is Coulee Dam, WA tap water safe to drink?
Coulee Dam's water quality earned a grade of A (90.7/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #35 out of 294 cities tested in Washington.
What contaminants are in Coulee Dam's water?
Lead was measured at 1.7 ppb (90th percentile). 3 violations are on record.
How is Coulee Dam'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 Dam?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Coulee Dam's water come from?
Coulee Dam's water is sourced from Surface water. The city has 1 water system serving approximately 1,359 residents.
What health violations has Coulee Dam's water system had?
Coulee Dam has 1 health-based violation on record. The most recent violation was recorded in July 2015. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
How does Coulee Dam's water compare to other cities?
Coulee Dam ranks #35 out of 294 cities in Washington (better than 88% of state cities) and #2088 out of 15744 cities nationally (87th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Coulee Dam's small water system affect quality?
Coulee Dam's system serves approximately 1,359 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 3 violations on record.