Water quality
Colorado water quality
According to USGS research and NPR reporting, parts of Colorado, especially the San Luis Valley, have naturally elevated arsenic in groundwater, with one USGS basin-fill study predicting large areas could meet or exceed the 10 ppb arsenic standard. Hardness tends to be high in areas drawing from mineral-rich aquifers. Most regulated public systems meet federal standards, but private well users face greater natural-contaminant risk.
Documented considerations
Arsenic
According to USGS modeling of Southwestern basin-fill aquifers, a large share of the area, including Colorado's San Luis Valley, was predicted to meet or exceed the 10 ppb arsenic standard; NPR reported rising valley arsenic linked to drought and aquifer overpumping.
Hardness
According to studies of the Rio Grande aquifer serving the San Luis Valley, calcium and magnesium levels indicate relatively hard water, consistent with mineral-rich groundwater common across Colorado.
Nitrates
According to USGS basin-fill modeling, parts of Colorado including the San Luis Valley were among areas predicted to approach or exceed the 10 mg/L nitrate standard, a concern mainly for private wells in agricultural areas.
Certified filters for Colorado's main concerns
- 7.2AquaTru Classic Countertop RO
A no-plumbing countertop 4-stage RO purifier certified to NSF standards for lead, PFAS, fluoride and arsenic with an efficient drain ratio.
FAQ
- Is there arsenic in Colorado drinking water?
- According to USGS research and NPR reporting, naturally occurring arsenic is elevated in parts of Colorado, especially the San Luis Valley. Regulated public systems must keep arsenic below 10 ppb, but private wells in affected areas can run higher.
- Is Colorado water hard?
- According to aquifer studies, water in many parts of Colorado, including the San Luis Valley's Rio Grande aquifer, is relatively hard due to dissolved calcium and magnesium. Hardness is an aesthetic and scaling issue rather than a health limit.
- Do I need to test my well in Colorado?
- Yes. Private wells are not federally regulated, and USGS data show parts of Colorado have elevated arsenic and nitrate, so testing for these contaminants is advisable.
Sources
- NPR - Risky Arsenic Levels in Colorado's San Luis Valley
- USGS - Predicted Nitrate and Arsenic in Southwestern Basin-Fill Aquifers
- Colorado Environmental Public Health Tracking - Drinking Water
Not sure how to read your local report? See our guide on reading a water quality report.