01The verdict: is Dayton water safe?
Dayton's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (88.9/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 824 residents using surface water (rivers, lakes, or reservoirs).
1 unresolved violation on record
EPA records show an open compliance item for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 4.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓3 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 ↓Dayton's drinking water received a grade of A- (88.9 out of 100), indicating good water quality. The city's 1 water system serves approximately 824 residents using surface water.
Lead levels were measured at 4.0 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 52 violations on record, including 3 health-based violations. 1 remains unresolved.
Dayton ranks #9 out of 63 cities in Wyoming 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, Dayton may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Dayton's water
Every contaminant flagged in Dayton, 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.
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. | 4.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Wyoming
Cities ranked by compounds detected Cu Copper in Wyoming
Cities ranked by 90th-percentile copper
03Dayton'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 52 violations on record, including 3 health-based violations. 1 remains unresolved.
9 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.
▲ Up 1 ppb since 2005. Latest reading: 4 ppb (2023) — 27% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Dayton's water comes from
Dayton'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.
1 system
1 water system, operated under local government ownership.
824 people
Residents served across Dayton'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 824 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| DAYTON, TOWN OF | WY5600202 | 824 | Surface Water |
05Pressure on Dayton'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.
Flood & storm history
1 federal disaster declaration on record for Sheridan County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Sheridan County is in D2 (severe 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 Dayton compares
Scores for nearby Wyoming cities on one line, with the average marked.
dashed line = Wyoming average (55/100)
Dayton scores 88.9/100 — above the Wyoming average of 55/100. It outscores 10 of 10 nearby cities. Full Wyoming rankings →
30.8 / 100FCasper, WY
41.8 / 100FGillette, WY
44.5 / 100CLaramie, WY
55.2 / 100CRock Springs, WY
64.8 / 100FJackson, WY
43.2 / 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 Dayton's water — not generic advice.
A basic carbon filter still helps
Dayton's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
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 Dayton 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 Dayton, WY tap water safe to drink?
Dayton's water quality earned a grade of A- (88.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #9 out of 63 cities tested in Wyoming.
What contaminants are in Dayton's water?
Lead was measured at 4.0 ppb (90th percentile). 52 violations are on record.
How is Dayton'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 Dayton?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Dayton's water come from?
Dayton's water is sourced from Surface water. The city has 1 water system serving approximately 824 residents.
What health violations has Dayton's water system had?
Dayton has 3 health-based violations on record. The most recent violation was recorded in July 2023. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
How does Dayton's water compare to other cities?
Dayton ranks #9 out of 63 cities in Wyoming (better than 86% of state cities) and #3169 out of 15382 cities nationally (79th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Dayton's small water system affect quality?
Dayton's system serves approximately 824 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 52 violations on record.