Laramie County, Wyoming: drinking water report. Laramie County sits in southeast Wyoming, anchored by Cheyenne, the state's capital and largest city.
Laramie County sits in southeast Wyoming, anchored by Cheyenne, the state's capital and largest city. The county relies primarily on groundwater from the Ogallala and Arikaree aquifers, supplemented by surface water from the Laramie River system. Rural communities outside Cheyenne operate on smaller municipal systems or private wells, creating a patchwork of water quality oversight across the county's 2,686 square miles.
Wyoming's agricultural legacy and energy development footprint shape water quality concerns across Laramie County. Nitrate contamination from fertilizer application appears in wells throughout the county, particularly in areas with intensive crop production or livestock operations. The Ogallala Aquifer, while generally protective, shows vulnerability to surface contamination where the water table sits shallow. Rural well owners face higher risk since private wells fall outside EPA regulation and testing requirements.
Cheyenne's municipal system undergoes regular testing under Safe Drinking Water Act standards, including the Lead and Copper Rule and UCMR monitoring for emerging contaminants. Like many cities with infrastructure built before 1986, older neighborhoods may have lead service lines or lead-containing plumbing components that can leach into tap water, especially in homes with corrosive water chemistry. The city treats for hardness and disinfects with chlorine, which forms byproducts that require ongoing management.
PFAS concerns are rising statewide, though Wyoming has conducted limited testing compared to other states. F.E. Warren Air Force Base, located just west of Cheyenne, used firefighting foam containing PFAS for decades. These persistent chemicals migrate through groundwater and surface water, potentially affecting nearby residential areas. The Department of Defense has begun testing and remediation at the base, but the full extent of off-base contamination remains unclear. Wyoming does not yet have enforceable PFAS limits beyond the federal regulations announced in 2024.
Private well owners should test annually for nitrates and coliform bacteria, with periodic screening for arsenic and uranium, which occur naturally in Wyoming geology. Urban residents can request water quality reports from their utility and consider testing if they live in pre-1986 homes or near industrial sites. Check your water for current data on your specific location, review our water filter guide for treatment options suited to Laramie County's contaminants, access your detailed report for comprehensive testing results, or visit the Wyoming state page for broader context on statewide water issues.