Is Greybull, WY Tap Water Safe to Drink?
Graded B, with 5 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
77/100
waterverge.com Greybull, WY — Water Quality Report
Greybull's drinking water received a grade of B (77 out of 100), indicating good water quality. The city's 3 water systems serve approximately 3,394 residents using groundwater.
Lead levels were measured at 2.0 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 95 violations on record, including 2 health-based violations. 5 remain unresolved.
What to know about Greybull's water
Greybull ranks #30 out of 65 cities in Wyoming for water quality, placing it mid-range in the state.
Greybull 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.
The system has seen 12 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Greybull, WY water safe to drink?
Greybull's drinking water has significant quality concerns based on EPA testing data. With a grade of B (77/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 3,394 residents using groundwater (wells).
Recent water quality updates for Greybull
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Greybull's water quality assessment. Grade: B (77/100).
Contaminants: Lead and Copper Rule.
Contaminants: Nitrate-Nitrite.
Contaminants: Combined Uranium, Combined Radium (-226 and -228), Radium-228.
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 Greybull's water supply.
Well within EPA limits.
Violation history
Greybull's water system has 95 total violations on record, including 2 health-based violations. 5 remain unresolved. 12 violations were issued in the last 5 years.
Flood & environmental risk
Big Horn 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. Local water sources include Bighorn River.
Where does Greybull's water come from?
Greybull's drinking water comes from groundwater (wells), supplied by 3 water systems serving approximately 3,394 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Bighorn River (river).
What Greybull residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Greybull'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.
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 droughtBig Horn 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
Big Horn 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. | 2.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Greybull compares by contaminant
Explore where Greybull ranks among all Wyoming cities for specific contaminants.
Water source & infrastructure
Where Greybull's water comes from
Greybull'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 3,394 people through 3 water systems.
Water bodies near Greybull
Greybull is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Greybull
| System Name | PWSID | Population | Source |
|---|---|---|---|
| GREYBULL, TOWN OF | WY5600022 | 3,260 | GW |
| GREYBULL HEIGHTS WATER USERS | WY5600230 | 84 | GWP |
| SCHAREN SUBDIVISION | WY5601666 | 50 | GWP |
How Greybull compares
Full Wyoming rankings →Greybull's score of 77/100 is above the average of 55/100 among major Wyoming cities. It outscores 8 of 10 nearby cities.
Nearby cities
View Wyoming rankings →About Greybull, WY
Wikipedia →Greybull is a town in central Big Horn County, Wyoming, United States. The population was 1,651 at the 2020 census.
Learn more about your water
Guides and resources related to Greybull's water quality findings.
Explore water quality across Big Horn
Frequently asked questions
Is Greybull, WY tap water safe to drink?
Greybull's water quality earned a grade of B (77/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #30 out of 65 cities tested in Wyoming.
What contaminants are in Greybull's water?
Lead was measured at 2.0 ppb (90th percentile). 95 violations are on record.
How is Greybull'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 Greybull?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Greybull's water come from?
Greybull's water is sourced from Groundwater. The city has 3 water systems serving approximately 3,394 residents.
What health violations has Greybull's water system had?
Greybull has 2 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 5 violations remain unresolved.
Is Greybull's groundwater at risk of contamination?
Greybull 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 95 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 Greybull's water compare to other cities?
Greybull ranks #30 out of 65 cities in Wyoming (better than 54% of state cities) and #9131 out of 15744 cities nationally (42th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.