Drinking Water Contaminants and Testing

Coliform Bacteria

Coliform bacteria are commonly found in our environment and the feces of humans and warm-blooded animals. The presence of coliform bacteria in drinking water may indicate that the water has been contaminated with disease-causing organisms (pathogens) like E coli or Salmonella. Pathogens are a public health risk because they can make people sick. We recommend testing for E coli and fecal coliforms once every year. For more information about coliform bacteria in drinking water: Coliform Bacteria and Drinking Water (DOH)

Nitrate

Here in the Columbia Basin, high levels of nitrate (NO3) can be found in some of the groundwater people rely on for drinking water. Nitrates in groundwater can come from natural plant or animal degradation, fertilizers, manure, agricultural runoff, or septic systems that aren't functioning properly. Wells that are most vulnerable to nitrate contamination include shallow wells, dug wells with casings that are not watertight, and wells with damaged, leaking casing or fittings.

The drinking water quality standard for nitrate is 10 milligrams per liter (mg/L). We recommend testing for nitrates in your well every 3 years.

Most adults are not at risk from nitrate contamination, but some health conditions, like pregnancy, Anemia, cardiovascular disease, lung disease, acidosis, or sepsis, can make people more at risk of health problems from high nitrate levels in drinking water. Infants are especially susceptible to nitrate contamination because nitrate reduces the ability of red blood cells to carry oxygen. This leads to a condition called methemoglobinemia or "blue baby syndrome." This condition gets its name because babies may get a blueish coloring to their skin due to a lack of oxygen in the blood.

View more information about nitrates.

PFAS/PFOA

Per- and Polyfluoroalkyl Substances (PFAS) are man-made chemicals that have been used in industry and consumer products worldwide since the 1940s. During production and use, PFAS can migrate into the soil, water, and air. Most PFAS (including PFOA and PFOS) do not break down, so they remain in the environment.

View more information on PFAS, including health concerns.