Navajo County, Arizona: drinking water report. Navajo County spans northeastern Arizona, encompassing communities including Show Low, Holbrook, Winslow,…
Navajo County spans northeastern Arizona, encompassing communities including Show Low, Holbrook, Winslow, Pinetop-Lakeside, and Snowflake. The county's water supply draws from a mix of groundwater aquifers, surface water from the Little Colorado River watershed, and snowmelt runoff in the higher elevations of the White Mountains. Rural and reservation areas often rely on individual wells or small community systems that face distinct monitoring and treatment challenges compared to larger municipal utilities.
Navajo County's water quality concerns reflect both its high-desert geology and its infrastructure limitations. Arsenic naturally occurs in groundwater throughout much of Arizona's Colorado Plateau region, where volcanic and sedimentary rocks release the element into aquifers. Communities relying on untreated or minimally treated groundwater may encounter arsenic levels above EPA's 10 parts per billion standard. The White Mountain communities drawing from forested watershed sources typically see lower arsenic but remain vulnerable to seasonal turbidity and microbial contamination following wildfires or heavy monsoon runoff.
Uranium presents another geology-driven concern in this region. The area's history of uranium mining, combined with naturally occurring uranium in certain rock formations, means some wells test above the EPA's 30 micrograms per liter maximum contaminant level. Small water systems and private wells in unincorporated areas face particular risk, as they often lack the continuous monitoring and treatment that larger utilities provide. Lead exposure in Navajo County tends to result from aging household plumbing rather than source water, especially in older homes built before lead-free solder became standard in 1986.
PFAS contamination data remains limited for many rural Arizona counties, but known sources include historic firefighting foam use at regional airports and military facilities. Navajo County's water systems have not been part of widespread UCMR5 testing under EPA's latest monitoring rule, though this reflects system size thresholds rather than absence of concern. Nitrate contamination from septic systems and livestock operations affects some shallow wells in agricultural areas, particularly around Snowflake and Taylor where groundwater sits closer to the surface.
Residents using private wells should test annually for arsenic, uranium, and nitrate, as these contaminants have no taste or odor. Those on municipal systems can request recent water quality reports from their provider to understand local contaminant levels. Check your water for current data on your specific area, review our water filter guide for treatment options suited to high-desert conditions, or access your detailed report for comprehensive contaminant information. Visit our Arizona state page for broader context on water quality across the state.
Drinking water is one exposure route. These federal datasets also cover Navajo County, AZ.
The EPA places Navajo County, AZ in Zone 2 - a moderate-risk category, with a predicted average indoor radon level between 2 and 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
32% of homes in Navajo County, AZ were built before 1980, and 4% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Navajo County, AZ averages 4.4 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide