Federal rules require that we test our water supply for more than 80 regulated contaminants and more than 50 unregulated chemicals even if they do not exist in our water.

We take weekly samples from throughout our water system to check for bacteria and chlorine residuals. Washington state Department of Health rules also require us to take 150 samples per month, however we routinely take more than 220.

We also sample our water supply for other microscopic organisms such as giardia and cryptosporidium. Sampling is required for cryptosporidium, and since this organism is blamed for making people sick in other cities around the world, we want to know what levels exist in our water. Samples taken during the past four years indicate low levels of cryptosporidium and coliform bacteria in our protected Green River water supply. In fact, the bacteria level found is far below the level allowed for unfiltered water systems.

Regulations allow up to 20 fecal coliform per sample of untreated river water; the Green River’s untreated raw water has a typical level between two and five per sample. These bacteria are quickly killed by the chlorine we add to your water.

Washington state Department of Health inspects our operations annually and suggests how we can improve. Reliable operation and treatment are always their most critical concern. Our water must meet or exceed the highest standard or we will not send it to you.