Is Colton, WA Tap Water Safe to Drink?
Graded A-, with 4 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
89.9/100
waterverge.com Colton, WA — Water Quality Report
Colton's drinking water received a grade of A- (89.9 out of 100), indicating good water quality. The city's 1 water system serves approximately 632 residents using groundwater.
Lead levels were measured at 4.1 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 37 violations on record, including 1 health-based violation. 4 remain unresolved.
What to know about Colton's water
Colton ranks #46 out of 294 cities in Washington for water quality, placing it above average in the state.
Colton 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, Colton may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Colton, WA water safe to drink?
Colton's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (89.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 632 residents using groundwater (wells).
Recent water quality updates for Colton
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Colton's water quality assessment. Grade: A- (89.9/100).
Contaminants: TTHM, Total Haloacetic Acids (HAA5).
Contaminants: TTHM.
Contaminants: Consumer Confidence Rule.
Federal disaster declaration (FEMA DR-3227). Coastal Storm event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-1100). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Colton's water supply.
Well within EPA limits.
Violation history
Colton's water system has 37 total violations on record, including 1 health-based violation. 4 remain unresolved.
Flood & environmental risk
Whitman County has experienced 7 federally declared disasters since 1964. 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 Colton's water come from?
Colton's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 632 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Colton residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Colton'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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Colton'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
D2 — severe droughtWhitman County is currently in D2 (severe 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
Whitman County has experienced 7 federally declared disasters since 1964. 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. | 4.1 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Colton compares by contaminant
Explore where Colton ranks among all Washington cities for specific contaminants.
Water source & infrastructure
Where Colton's water comes from
Colton'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 632 people through 1 water system.
Water systems serving Colton
| System Name | PWSID | Population | Source |
|---|---|---|---|
| COLTON WATER DEPARTMENT | WA5314100 | 632 | GW |
How Colton compares
Full Washington rankings →Colton's score of 89.9/100 is above the average of 53/100 among major Washington cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Washington rankings →About Colton, WA
Learn more about your water
Guides and resources related to Colton's water quality findings.
Explore water quality across Whitman
Frequently asked questions
Is Colton, WA tap water safe to drink?
Colton's water quality earned a grade of A- (89.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #46 out of 294 cities tested in Washington.
What contaminants are in Colton's water?
Lead was measured at 4.1 ppb (90th percentile). 37 violations are on record.
How is Colton'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 Colton?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Colton's water come from?
Colton's water is sourced from Groundwater. The city has 1 water system serving approximately 632 residents.
What health violations has Colton's water system had?
Colton has 1 health-based violation on record. The most recent violation was recorded in January 2018. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.
Is Colton's groundwater at risk of contamination?
Colton 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 37 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 Colton's water compare to other cities?
Colton ranks #46 out of 294 cities in Washington (better than 84% of state cities) and #2532 out of 15744 cities nationally (84th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Colton's small water system affect quality?
Colton's system serves approximately 632 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 37 violations on record.