Water Quality: Evergreen, CO

Probable human carcinogen that increases the risk of kidney and thyroid cancers.

Common source: Ozonation of bromide-containing water; used as flour improver

EPA limit: 0.010 mg/L (10 ppb)

Eye and nose irritation at high levels; long-term exposure above the MCL may cause liver and kidney damage.

Common source: Water treatment disinfectant added to kill harmful microorganisms

EPA limit: 4.0 mg/L (MRDL — Maximum Residual Disinfectant Level)

Broad category of chemicals formed during disinfection, associated with increased cancer risk and adverse reproductive effects.

Common source: Reaction of disinfectants (chlorine, ozone, chloramines) with organic matter

Indicates direct fecal contamination; associated with diarrhea, cramps, nausea, and potential severe illness.

Common source: Human and animal fecal waste

EPA limit: Zero tolerance (any positive triggers violations)

Haloacetic acids are associated with increased cancer risk and potential reproductive and developmental effects.

Common source: Reaction of chlorine disinfectants with organic matter in treated water

EPA limit: 0.060 mg/L (60 ppb)

Hair loss, nail brittleness, and nervous system damage at elevated concentrations.

Common source: Natural geological deposits, mining discharges, oil refinery waste

EPA limit: 0.05 mg/L (50 ppb)

Trihalomethanes and haloacetic acids that increase cancer risk and may cause adverse reproductive outcomes.

Common source: Chlorine disinfection reacting with natural organic matter in source water

EPA limit: TTHM: 0.080 mg/L; HAA5: 0.060 mg/L

Not a direct health risk but reacts with disinfectants to form carcinogenic byproducts such as trihalomethanes.

Common source: Decaying plant material, algae, soil organic matter in source water

EPA limit: Treatment technique (must reduce TOC based on source water level)