Are high levels of Coliform and Nitrates contaminating your water?

Testing Your Water For Contaminants

Yakima, Benton & Kittitas Counties & Your Water Supply


The quality of your water affects your health and the health of your family.

It is important to be informed about the water you use in your home.

Private well users are responsible for testing their own water though even if you are on a public water system problems could develop.

Public Water System Vs Private Water Supply

If your drinking water does  come from a public water system the supplier will do water testing for you, though it is your responsibility to test for pitting of pipes, plumbing and facets.

If you get your drinking water from a household well or you are on a private water supply, you alone are responsible for assuring that it is safe and of adequate quality for your needs. The federal and state governments do not regulate privately owned wells in Washington. For this reason, routine testing for a few of the most common contaminants is highly recommended. Even if you currently have a safe, pure water supply, regular testing can be valuable because:

  • It establishes a record of water quality.
  • Helpful an abrupt or noticeable change in your water

What should you test for and how often?

Drinking contaminated water is a health risk and some contaminants cannot be seen, smelled, or tasted. Two of the most common contaminants in drinking water are (1) Coliform Bacteria and (2) Nitrate, which can be harmful to your health and should be tested at least once a year.

1. Coliforms are bacteria that are always present in the digestive tracts of animals, including humans, and are found in their wastes. They are also found in plant and soil material.

There are 3 types of Coliforms

  1. Total Coliforms include bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste.
  2. Fecal coliforms are the group of the total coliforms that are considered to be present specifically in the gut and feces of warm-blooded animals. Because the origins of fecal coliforms are more specific than the origins of the more general total coliform group of bacteria, fecal coliforms are considered a more accurate indication of animal or human waste than the total coliforms.
  3. Escherichia coli (E. coli) are the major species in the fecal coliform group. Of the five general groups of bacteria that comprise the total coliforms, only E. coli is generally not found growing and reproducing in the environment. Consequently, E. coli is considered the species of coliform bacteria that is the best indicator of fecal pollution and the possible presence of pathogens.

The most basic test for bacterial contamination of a water supply is the test for total coliform bacteria. Total coliform counts give a general indication of the sanitary condition of a water supply.

Is Coliform Bacteria Harmful?

Most coliform bacteria do not cause disease. However, some rare strains of E. coli can cause serious illness. Recent outbreaks of disease caused by E. coli have generated much public concern about this organism. E. coli has been found in cattle, chickens, pigs, and sheep. Most of the reported human cases have been due to eating under cooked hamburger. Cases of E. coli caused by contaminated drinking water supplies are rare.

Coliform Testing

Testing for bacteria is the only reliable way to know if your water is safe. You cannot tell by the look, taste, or smell of the water if disease-causing organisms are in it. The Washington State Department of Health recommends that well owners test their water for coliform bacteria at least once a year. If you have experienced bacteria problems in the past, it is recommended that you test your well more frequently.

2. Nitrate is a naturally occurring chemical made of nitrogen and oxygen. Nitrate is found in air, soil, water, and plants. Much of the nitrate in our environment derives from decomposition of plants and animal wastes.

  • Health concerns when drinking water with high levels of Nitrates or Nitrites.
  • Poisoning can occur when infants drink formula made with nitrate or nitrite- contaminated tap water.
  • The infant’s blood is less able to carry oxygen due to the poisoning.
  • Affected infants develop a blue-grey color and need emergency medical help immediately.
  • Infants under six months of age are more susceptible.
  • Nitrosamines are being studied for long-term links to cancer. No standards have been set for this yet.

Two ways of reporting Nitrate concentrations:

Know the difference!

 When your report on the water test comes back from the lab, the nitrate concentration can be reported either as nitrate (NO3) or as nitrate-nitrogen (NO3-N).

Knowing which reporting system is being utilized is important because the acceptable concentrations of each are considerably different. If the lab reports its results as nitrate, the drinking water quality standard is 45 mg/l. If the lab reports its results as nitrate-nitrogen, the drinking water quality standard is 10 mg/l. A milligram per liter (mg/l) is also equal to one part per million (ppm).

If you are unsure of how to interpret the report, contact the lab, or the local health department. It is important to check the lab report carefully because the two systems can be interchanged.

Your Water should also be tested when:

  • Rotten egg odor
  • Pitting of pipes, plumbing, faucets
  • Rapid wear of water treatment equipment
  • Nearby areas of intensive agriculture
  • Feedlots nearby
  • Odor of gasoline
  • Station or buried fuel tanks
  • Dump, junkyard landfill
  • Factory operation nearby
  • Salty taste in water
  • Salted roadway near

Where do I go to get my water tested?

State and local health or environmental departments often test for nitrates, total coliforms, fecal coliforms, volatile organic compounds. Health or environmental departments, or county governments should also have a list of the state-certified laboratories in your area that test for a variety of Water Quality Indicators and contaminants.

Drinking Water Testing

Taking Sample Yourself: Samples must be delivered to the lab immediately after retrieving.There are several locations where residents can take samples of their drinking water for water quality testing.

labListed below are  a few County & Private agencies to help you get started.

Cascade Analytical, Inc.

1008 W. Ahtanum Yakima, WA 98903

(509) 452-7707

Valley Environmental Laboratory

150 W Yakima Ave Suite 200 Yakima, WA 98902

(509) 836-2020

Ag Health Laboratories

445 Barnard Blvd Sunnyside, WA 98944

(509) 836-202

Benton Franklin Health District

7102 W Okanogan Pl Kennewick WA

(509) 460 4200

Kittitas County Health Department

507 N Nanum St Suite 102 Ellensburg WA 98926

(509) 962-7515

                  Considering a home water treatment?

Find out what is in your water and what you might want to remove before contacting potential dealers. Different treatment types remove different pollutants or impurities and no one device does it all. Be informed so you can make the right decision.


We hope this article has been helpful. For more information about your water well need, please visit us at our website 




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