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Environmental Health: Water Lab FAQs

Frequently Asked Questions (FAQs) - Water Laboratory

Below are some of the questions asked most frequently about drinking water wells.

What is Groundwater?

Ground water is a vast resource that underlies the earth's surface. Another term for ground water is aquifer. Water wells are drilled to tap into this valuable resource.

Ground water occurrence, its vulnerability to contamination, and its value and use as a resource, vary from place to place. The vulnerability of ground water to contamination depends on hydrogeologic conditions, such as the extent and location of the recharge area, the depth of ground water, the soil and rock composition overlying the aquifer, the recharge rate, and the specific properties of the chemical contaminants.

Ground water contamination has been documented in every state of the United States. However, the exact extent of ground water contamination is not known. It has been estimated that less than 2 percent of ground water is contaminated at this point in time.

What are some common contaminants?

Understanding and identifying the potential sources of contamination of your
well is a first step toward assuring safe drinking water for you and your family. Some of these potential threats from nature-naturally occurring contaminants-that, if present in your drinking water, may present a health risk. These include microorganisms, radioactive elements, nitrates, heavy metals and fluoride.

Other potential sources from past or present human activity-things that we do, make, and use, which may result in the pollution of the water we drink. These include bacteria and nitrates, household plumbing materials, fertilizers and pesticides, industrial products and wastes, household wastes, and water treatment chemicals.

In Missoula County, one of the most common complaints concerns water with bad odors or flavors that may also be discolored. Generally these problems are usually Iron Bacteria or Sulfur Bacteria.

Do I need to test my well water for contamination?

Household wells should be tested periodically. Ideally, the time to test your water is during spring run-off and high groundwater times. If you are likely to have water well contamination, you will probably see it at these times.

Have a competent laboratory or health department test your water annually for total coliform bacteria (from human and animal wastes), nitrates, total dissolved solids, and pH levels. If you suspect other contaminants are present, tests for these should also be done.

Chemical testing can be expensive, so you will want to reduce the list by identifying potential contaminants specific to your situation. If you have no idea what is wrong with your well, check the Yellow Pages under Well Testing to find the phone number of a consultant who may be able give you some guidance by phone.

Again, local experts may be of assistance. In many cases, county health departments provide testing and analysis for bacteria. For other contaminants, the health department has a list of state certified laboratories.

Our laboratory provides sampling bottles and instructions for you to use. Follow these instructions carefully to ensure proper testing and accurate results.

Your water should also be tested after replacing or repairing part of the well system (piping, pump, or the well itself) or if you notice a change in the water's look, taste, or smell.

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