Have you had your well water tested lately?

It is recommended that you test your private water on an annual basis, looking for total coliform bacteria and nitrates. A more comprehensive test to categorize your overall water quality, including parameters such as pH and hardness along with specific conductivity and metals (calcium, magnesium, sodium, potassium, manganese, iron, copper, lead and arsenic), can be done every five years. This is called a full domestic analysis.

Below, we list several water quality indicators (WQIs) and contaminants that should be tested. A WQI test is a test that measures the presence and amount of certain germs in water. In most cases, the presence of WQIs is not the cause of sickness; however, they are easy to test for and their presence may indicate the presence of sewage and other disease-causing germs from human and/or animal feces.


Water Quality Indicators


Total Coliforms

Coliform bacteria are microbes found in the digestive systems of warm-blooded animals, in soil, on plants, and in surface water. These microbes typically do not make you sick; however, because microbes that do cause disease are hard to test for in the water, “total coliforms” are tested instead. If the total coliform count is high, then it is very possible that harmful germs like viruses, bacteria, and parasites might also be found in the water.


Fecal Coliforms / Escherichia coli (E. coli)

Fecal coliform bacteria are a specific kinds of total coliform. The feces (or stool) and digestive systems of humans and warm-blooded animals contain millions of fecal coliforms. E. coli is part of the fecal coliform group and may be tested for by itself. Fecal coliforms and E. coli are usually harmless. However, a positive test may mean that feces and harmful germs have found their way into your water system. These harmful germs can cause diarrhea, dysentery, and hepatitis. It is important not to confuse the test for the common and usually harmless WQI E. coli with a test for the more dangerous germ E. coli O157:H7.



The pH level tells you how acidic or basic your water is, and different levels can change how your water looks and tastes. If the pH of your water is too low or too high, it could damage your pipes, cause heavy metals like lead to leak out of the pipes into the water, and eventually make you sick.



Nitrate is naturally found in many types of food. However, high levels of nitrate in drinking water can make people sick. Nitrate in your well water can come from animal waste, private septic systems, wastewater, flooded sewers, polluted storm water runoff, fertilizers, agricultural runoff, and decaying plants. The presence of nitrate in well water also depends on the geology of the land around your well. A nitrate test is recommended for all wells. If the nitrate level in your water is higher than the EPA standards, you should look for other sources of water or ways to treat your water.


When to have your well tested

At a minimum, check your well every spring to make sure there are no mechanical problems. Have the water tested once each year for total coliform bacteria, nitrates, total dissolved solids, and pH levels. If you suspect other contaminants, you should test for those as well. However, spend time identifying potential problems as these tests can be expensive.

The best way to start is to consult a local expert, such as the local health department, about local contaminants of concern. You should also have your well tested if:

• There are known problems with well water in your area

• You have experienced problems near your well (i.e., flooding, land disturbances, and nearby waste disposal sites)

• You replace or repair any part of your well system

• You notice a change in water quality (i.e., taste, color, odor)


How to Test Your Well

Water samples must be collected in special laboratory bottles. Bottles for several labs in the area are available at the Gallatin Local Water Quality District. The bottles are free and available at these locations:


Gallatin Local Water Quality District

215 W. Mendenhall, Suite 300, Bozeman




Environmental Health Services

215 W. Mendenhall, Room 108, Bozeman




**Please note that if the well serves a licensed facility such as a trailer court, campground, RV Park, hotel, motel, restaurant, tattoo facility, etc. you may be subject to additional requirements. Contact Environmental Health Services at 406.582.3120 if you are unsure.


Where to Have Water Tested

Follow this link for accredited labs in the State of Montana:




Contact Environmental Health Services at




Go here for more information about other aspects of a Healthy Home & Environment in Gallatin County.