Well Water in Wyoming
Contaminant risks, testing requirements, and treatment recommendations for private well owners in Wyoming.
Wyoming Geology and Groundwater
Wyoming sits on Rocky Mountain bedrock and Wind River formation. This geology directly determines what contaminants are likely in private well water. Based on this geology, Wyoming well owners face elevated risk for uranium from bedrock geology. Moderate risk exists for arsenic, radon, nitrate.
Contaminant Risk Profile
| Contaminant | Risk Level | Why |
|---|---|---|
| Arsenic | Moderate risk | Some geological zones have elevated levels. Test recommended. |
| Nitrate | Moderate risk | Some areas near farmland or septic systems may have elevated levels. |
| Radon | Moderate risk | Some bedrock types in this state produce radon. |
| PFAS | Low risk | Fewer known contamination sources, but PFAS can travel far through groundwater. |
| Iron/Manganese | Moderate risk | Found in some wells depending on local geology. |
| Uranium | Elevated risk | Natural occurrence in granitic/metamorphic bedrock. EPA MCL: 30 ppb. |
| Fluoride | Moderate risk | Some wells may have naturally elevated levels. |
How Wyoming Compares: Municipal Water Data
CheckMyTap tracks water quality for 7 cities in Wyoming. While these numbers reflect municipal water (not private wells), they indicate the baseline mineral content of Wyoming's water sources. Private wells often draw from the same aquifers but with less treatment.
| Metric | Wyoming Average | National Average |
|---|---|---|
| Hardness | 168 PPM (hard) | 170 PPM |
| Hardness range | 66 - 245 PPM | 25 - 400+ PPM |
| Lead (avg municipal) | 4.6 ppb | 3.2 ppb |
| Nitrate (avg municipal) | 0.5 mg/L | 1.1 mg/L |
| Cities with PFAS detected | 1 of 7 | ~45% nationally |
| Cities exceeding PFAS MCL (4 ppt) | 1 |
Hardest water in Wyoming: Gillette (245 PPM), Rock Springs (200 PPM), Casper (196 PPM), Cheyenne (190 PPM), Riverton (180 PPM).
Testing Requirements in Wyoming
Wyoming does not have a statewide mandatory testing requirement for existing private wells. Regardless of state requirements, the EPA recommends testing annually for:
- Every year: Total coliform bacteria, E. coli, nitrate, pH, and total dissolved solids
- At least once: Arsenic, lead, copper, fluoride, and any contaminant identified as a local risk
- Recommended for Wyoming: Radon in water (granitic bedrock states have higher risk)
- Recommended for Wyoming: Uranium, especially in areas with granitic or metamorphic bedrock
- After events: Retest after flooding, well repairs, nearby construction, or any change in taste/color/odor
Recommended Treatment for Wyoming Wells
Based on Wyoming's geology and common contaminant risks, these treatment systems address the most likely issues:
Removes arsenic, uranium, and most dissolved contaminants from drinking water
Learn moreWyoming groundwater averages 168 PPM. A softener prevents scale damage, reduces energy waste, and extends appliance life
Learn moreKills bacteria and viruses without chemicals. Recommended for all well water systems
Frequently Asked Questions
Is well water in Wyoming safe to drink?
Well water quality in Wyoming varies significantly by location and geology. Wyoming sits on Rocky Mountain bedrock and Wind River formation. Key concerns include uranium from bedrock geology. The only way to know your specific water quality is to test it. Use our free interpreter to understand your results.
How often should I test my well water in Wyoming?
The EPA recommends testing annually for bacteria (total coliform, E. coli), nitrate, total dissolved solids, and pH. Given Wyoming's arsenic risk, test for arsenic at least once and after any changes to your well. Radon testing is also recommended in Wyoming. Test more frequently if you notice changes in taste, color, or odor, or after flooding, nearby construction, or well repairs.
Does Wyoming require well water testing?
Wyoming does not have a statewide mandatory testing requirement for existing private wells. However, the EPA strongly recommends annual testing regardless of state requirements. Your county health department may have additional local requirements.
What is the average water hardness in Wyoming?
Municipal water in Wyoming averages 168 PPM across 7 cities tracked by CheckMyTap, ranging from 66 to 245 PPM. Private well water typically runs 20-50% harder than city water because groundwater has more contact time with mineral formations. Most Wyoming well owners benefit from a water softener. Check your city's data.