Is Sumas, WA Tap Water Safe to Drink?
Graded A-, with 5 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
88.5/100
waterverge.com Sumas, WA — Water Quality Report
Sumas's drinking water received a grade of A- (88.5 out of 100), indicating good water quality. The city's 2 water systems serve approximately 2,352 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 69 violations on record, including 17 health-based violations. 5 remain unresolved.
What to know about Sumas's water
Sumas ranks #58 out of 294 cities in Washington for water quality, placing it above average in the state.
Sumas 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, Sumas may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Sumas, WA water safe to drink?
Sumas's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (88.5/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 2,352 residents using groundwater (wells).
Recent water quality updates for Sumas
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Sumas's water quality assessment. Grade: A- (88.5/100).
Federal disaster declaration (FEMA DR-3629). Flood event — may have impacted local water infrastructure.
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-4635). Flood event — may have impacted local water infrastructure.
Contaminants: Lead and Copper Rule.
Contaminants: Consumer Confidence Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Sumas's water supply.
Well within EPA limits.
Violation history
Sumas's water system has 69 total violations on record, including 17 health-based violations. 5 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
Whatcom County has experienced 10 federally declared disasters since 1979. 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 Nooksack R Overflow, Nooksack River, Sumas River.
Where does Sumas's water come from?
Sumas's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 2,352 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Nooksack R Overflow (river), Nooksack River (river), Sumas River (river).
What Sumas residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Sumas'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.
Sumas'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
Top industrial polluters within 10 miles of Sumas
Industrial polluters nearby
Reported releases to surface water by facilities near Sumas, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
DARIGOLD - LYNDEN LYNDEN, WA98264 | — | — | 9.0 mi |
IKO PACIFIC INC. SUMAS, WA98295 | — | — | 0.6 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Whatcom County has experienced 10 federally declared disasters since 1979. 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 Sumas compares by contaminant
Explore where Sumas ranks among all Washington cities for specific contaminants.
Water source & infrastructure
Where Sumas's water comes from
Sumas'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 2,352 people through 2 water systems.
Water bodies near Sumas
Sumas is located near 3 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Sumas
| System Name | PWSID | Population | Source |
|---|---|---|---|
| SUMAS WATER DEPT | WA5384870 | 1,740 | GW |
| SUMAS RURAL WATER ASSOCIATION | WA5384850 | 612 | GWP |
How Sumas compares
Full Washington rankings →Sumas's score of 88.5/100 is above the average of 53/100 among major Washington cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Washington rankings →About Sumas, WA
Learn more about your water
Guides and resources related to Sumas's water quality findings.
Explore water quality across Whatcom
Frequently asked questions
Is Sumas, WA tap water safe to drink?
Sumas's water quality earned a grade of A- (88.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #58 out of 294 cities tested in Washington.
What contaminants are in Sumas's water?
Lead was measured at 0.0 ppb (90th percentile). 69 violations are on record.
How is Sumas'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 Sumas?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Sumas's water come from?
Sumas's water is sourced from Groundwater. The city has 2 water systems serving approximately 2,352 residents.
What health violations has Sumas's water system had?
Sumas has 17 health-based violations on record. The most recent violation was recorded in December 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 5 violations remain unresolved.
Is Sumas's groundwater at risk of contamination?
Sumas 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 69 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 Sumas's water compare to other cities?
Sumas ranks #58 out of 294 cities in Washington (better than 80% of state cities) and #3419 out of 15744 cities nationally (78th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.