01The verdict: is Dillon water safe?
Dillon's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (67.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 4 water systems serve approximately 9,018 residents using surface water (rivers, lakes, or reservoirs).
Copper is over its legal limit
Measured at 1.72 mg/L against the EPA Action Level of 1.3 mg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓9K people, 4 systems
All figures on this page come from federal EPA compliance and testing data for the systems serving this city.
See the systems ↓17 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Dillon's drinking water received a grade of C+ (67.8 out of 100), indicating fair water quality. The city's 4 water systems serve approximately 9,018 residents using surface water.
Lead levels were measured at 8.0 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 34 violations on record, including 0 health-based violations. 9 remain unresolved.
Dillon ranks #130 out of 244 cities in Colorado for water quality, placing it below 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. While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection. The system has seen 17 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
02What's in Dillon's water
Every contaminant flagged in Dillon, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Over Limit — EPA Action Level: 1.3 mg/L
Exceeds the EPA action level. Copper leaches from household plumbing — flush taps for 30 seconds before drinking, and consider a certified filter.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. | 8.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.72 | 1.3 | mg/L | Inorganic | Over Limit |
Cities ranked by 90th-percentile lead PF PFAS in Colorado
Cities ranked by compounds detected Cu Copper in Colorado
Cities ranked by 90th-percentile copper
03Dillon's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 34 violations on record, including 0 health-based violations. 9 remain unresolved.
5 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 108 ppb since 1993. Latest reading: 0 ppb (2025) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
▲ Up 0.32 mg/L since 1993. The latest reading (1.7 mg/L, 1994) is over the action level. Sampled at higher-risk homes (90th percentile).
04Where Dillon's water comes from
Dillon's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface Water
Rivers, lakes, or reservoirs — more exposed to runoff, agriculture, and seasonal swings than groundwater.
Local treatment
Multi-barrier treatment: coagulation, sedimentation, filtration, and disinfection to meet EPA standards.
4 systems
4 water systems, operated under local government ownership.
9,018 people
Residents served across Dillon's service area.
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 9,018 people through 4 water systems.
| System name | PWSID | Population | Source |
|---|---|---|---|
| DILLON TOWN OF | CO0159035 | 3,254 | Surface Water |
| DILLON VALLEY DISTRICT | CO0159040 | 3,063 | Surface Water |
| EAST DILLON WD | CO0159045 | 2,501 | Ground Water Under Influence |
| HAMILTON CREEK MD | CO0159063 | 200 | Surface Water |
Water bodies near Dillon
As a surface-water system, these water bodies may directly influence Dillon's drinking water supply.
05Pressure on Dillon's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
1 facility within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
1 federal disaster declaration on record for Summit County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Summit County is in D4 (exceptional drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Dillon compares
Scores for nearby Colorado cities on one line, with the average marked.
dashed line = Colorado average (45/100)
Dillon scores 67.8/100 — above the Colorado average of 45/100. It outscores 9 of 10 nearby cities. Full Colorado rankings →
39.6 / 100FAurora, CO
38.1 / 100FColorado Springs, CO
33.5 / 100DFort Collins, CO
46.8 / 100FLakewood, CO
36.9 / 100FThornton, CO
38 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Dillon's water — not generic advice.
Filter drinking & cooking water
NSF-certified water filter. Lead detected at 8.0 ppb
Compare tested filters →Flush taps & check your service line
Lead leaches from pipes as water sits. Run cold water 30 seconds before drinking (especially mornings), and ask the utility whether your address still has a lead service line.
Lead risks explained →Watch for Dillon alerts
We refresh EPA data monthly and surface new violations, advisories, and boil-water notices for your county on this page.
All water alerts →Frequently asked questions
Is Dillon, CO tap water safe to drink?
Dillon's water quality earned a grade of C+ (67.8/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #130 out of 244 cities tested in Colorado.
What contaminants are in Dillon's water?
Lead was measured at 8.0 ppb (90th percentile). 34 violations are on record.
How is Dillon'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 Dillon?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Dillon's water come from?
Dillon's water is sourced from Surface water. The city has 4 water systems serving approximately 9,018 residents.
How does Dillon's water compare to other cities?
Dillon ranks #130 out of 244 cities in Colorado (better than 47% of state cities) and #11010 out of 15382 cities nationally (28th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.