Is Thermopolis, WY Tap Water Safe to Drink?
Graded D, with 44 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
45.6/100
waterverge.com Thermopolis, WY — Water Quality Report
Thermopolis's drinking water received a grade of D (45.6 out of 100), indicating poor water quality. The city's 6 water systems serve approximately 4,039 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 130 violations on record, including 13 health-based violations. 44 remain unresolved.
What to know about Thermopolis's water
Thermopolis ranks #56 out of 65 cities in Wyoming for water quality, placing it among the lowest-rated 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.
The system has seen 29 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Thermopolis, WY water safe to drink?
Thermopolis's drinking water has significant quality concerns based on EPA testing data. With a grade of D (45.6/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 6 water systems serve approximately 4,039 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Thermopolis
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Thermopolis's water quality assessment. Grade: D (45.6/100).
Contaminants: Revised Total Coliform Rule.
Contaminants: Consumer Confidence Rule.
Contaminants: Consumer Confidence Rule.
Federal disaster declaration (FEMA DR-557). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Thermopolis's water supply.
Well within EPA limits.
Violation history
Thermopolis's water system has 130 total violations on record, including 13 health-based violations. 44 remain unresolved. 29 violations were issued in the last 5 years.
Flood & environmental risk
Hot Springs County has experienced 1 federally declared disaster since 1978. 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 Thermopolis's water come from?
Thermopolis's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 6 water systems serving approximately 4,039 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment.
What Thermopolis residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Thermopolis'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.
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 droughtHot Springs 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
Hot Springs County has experienced 1 federally declared disaster since 1978. 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. | 4.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Thermopolis compares by contaminant
Explore where Thermopolis ranks among all Wyoming cities for specific contaminants.
Water source & infrastructure
Where Thermopolis's water comes from
Thermopolis'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 4,039 people through 6 water systems.
Water systems serving Thermopolis
| System Name | PWSID | Population | Source |
|---|---|---|---|
| THERMOPOLIS, TOWN OF | WY5600056 | 2,775 | SW |
| SOUTH THERMOPOLIS W&S DISTRICT | WY5601083 | 450 | SWP |
| LUCERNE WATER AND SEWER DIST. | WY5600935 | 350 | GWP |
| EAST THERMOPOLIS, TOWN OF | WY5600226 | 254 | SWP |
| RED LANE DOMESTIC WATER, INC. | WY5600232 | 110 | SWP |
| OWL CREEK WATER DISTRICT | WY5601673 | 100 | SWP |
How Thermopolis compares
Full Wyoming rankings →Thermopolis's score of 45.6/100 is below the average of 55/100 among major Wyoming cities. It outscores 5 of 10 nearby cities.
Nearby cities
View Wyoming rankings →About Thermopolis, WY
Wikipedia →Thermopolis is the county seat and most populous town in Hot Springs County, Wyoming, United States. As of the 2020 census, Thermopolis had a population of 2,725.
Learn more about your water
Guides and resources related to Thermopolis's water quality findings.
Explore water quality across Hot Springs
Frequently asked questions
Is Thermopolis, WY tap water safe to drink?
Thermopolis's water quality earned a grade of D (45.6/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #56 out of 65 cities tested in Wyoming.
What contaminants are in Thermopolis's water?
Lead was measured at 4.0 ppb (90th percentile). 130 violations are on record.
How is Thermopolis'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 Thermopolis?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Thermopolis's water come from?
Thermopolis's water is sourced from Surface water. The city has 6 water systems serving approximately 4,039 residents.
What health violations has Thermopolis's water system had?
Thermopolis has 13 health-based violations on record. The most recent violation was recorded in December 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 44 violations remain unresolved.
How does Thermopolis's water compare to other cities?
Thermopolis ranks #56 out of 65 cities in Wyoming (better than 14% of state cities) and #14130 out of 15744 cities nationally (10th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.