How do you know your drinking water is safe? It’s simple - test it. Generally, private water supplies should be annually tested for nitrate and bacterial contamination. Otherwise, drinking water should be tested if:
- you notice a change in your water quality;
- people using the water suffer from an illness that may be waterborne;
- there is a flood or large storm that may have carried contaminants to your wellhead;
- maintenance work has been performed on the well;
- a pregnant woman, a woman anticipating pregnancy, or an infant under the age of six months becomes a water user.
What to test for?
There is a broad range of potential chemical and biological groundwater contaminants which can find their way into your water supply. Testing for all of them would be extremely expensive. By assessing which contaminants your well is at highest risk from you can determine what to test for.
| Problem or Concern |
Symptoms |
Water Test to Consider |
| Appearance |
Frothy, foamy |
Detergents |
| Appearance |
Black flakes |
Manganese |
| Appearance |
Brown, yellow, or reddish |
Iron |
| Odor or taste |
Rotten egg |
Hydrogen sulfide |
| Odor or taste |
Metallic |
pH, iron, zinc, copper, lead |
| Odor or taste |
Salty |
Total dissolved solids, chloride, sodium, sulfates |
| Odor or taste |
Black flakes |
Manganese |
| Odor or taste |
Septic, musty, or earthy |
Coliform bacteria, iron |
| Odor or taste |
Soapy |
Surfactants, detergents |
| Odor or taste |
Gasoline or oil |
Hydrocarbon scan, volatile organic chemicals (VOCs) |
| Appearance |
Black flakes |
Manganese |
| Stains on fixtures or clothing |
Black |
Manganese |
| Stains on fixtures or clothing |
Green or blue |
Copper |
| Stains on fixtures or clothing |
Reddish-brown slime |
Iron bacteria |
| Stains on fixtures or clothing |
White deposits, soap scum |
Hardness (calcium and magnesium) |
| Uses and symptoms |
White deposits, soap scum |
White deposits, soap scum |
| Uses and symptoms |
Discoloration of children's teeth |
Fluoride |
| Uses and symptoms |
Gastrointestinal illness |
Coliform bacteria, sulfates, giardia |
| Uses and symptoms |
Water supply used for infants less than six months old, pregnant or nursing women, or elderly with genetically impaired enzyme system |
Nitrates |
| Corrosion |
Pitting of plumbing fixtures and deposits on sinks and plumbing pipes. |
Corrosivity, pH, lead, zinc, manganese, copper, iron, sulfates, chloride |
| If you suspect or observe: |
Leaking fuel tank |
Hydrocarbon scan, VOCs |
| If you suspect or observe: |
Road salt |
Total dissolved solids, pH, VOCs, heavy metals |
| If you suspect or observe: |
Landfills |
Total dissolved solids, pH, VOCs, heavy metals |
| If you suspect or observe: |
Sludge utilization |
Coliform bacteria, nitrate, metals (lead, cadmium) |
| If you suspect or observe: |
Septic system failure |
Coliform bacteria, nitrate, detergents, total dissolved solids, chloride, sodium, sulfates |
| If you suspect or observe: |
Intensive agricultural use |
Coliform bacteria, nitrate, pesticide scan, pH, total dissolved solids |
It is best to perform coliform bacteria tests in the spring during wet weather. This is when bacteria is most likely to be found because runoff and excess soil moisture can carry contaminants into shallow groundwater sources or through well defects. Test for other substances when specific contamination is suspected. This might be the result of a spill or backflow, use of harmful products in close proximity to the well, or other similar events. Any noticeable change in water taste, color, or smell signals the need for testing.
Where can I get my water tested?
Many commercial laboratories in Montana have the facilities to test water. Prices vary but will often be competitive with state labs. When obtaining laboratory services for water testing, look for three things:
- Guidance with collecting samples
- Analytical services available
- Assistance with interpretation of results
The State of Montana requires certified labs to adhere to the State of Montana Drinking Water Certification requirements which have been adapted from the EPA Manual for the Certification of Laboratories Analyzing Drinking Water.
Check the link below for labs in your area.
Certified MT Drinking Water Testing Labs
How do I go about getting a test done?
After you have thought about what to test your water for, choose a lab from the sources above. Next contact the lab to find out about containers and shipping of samples. Most labs will send you sample bottles and instructions for free. If there is a lab in your area, you may want to transport the sample yourself to ensure timely delivery. Samples need to get to the lab quickly, preferably within 24 hours of collection.
Water Sampling Tips
- Use a clean, indoor faucet.
- Try to avoid threaded taps, leaky, or swing-type faucets.
- Do not use a dirty or contaminated tap.
- Do not sample through a hose or treatment device.
- Always sample the cold water.
- Allow the water to run in a steady stream at least five minutes before collecting the sample or until the pump runs.
- Do not set the bottle cap down.
- Do not touch the inside of the cap or bottle.
- Do not allow the cap or bottle to touch the faucet.
- Do not rinse the bottle.
- Maintain a steady low-flow stream.
- Fill the container to the fill line. Do not overfill.
- Seal the container as soon as it is filled.
- Enclose submission slip and proper payment with sample.
- Send/transport samples to the lab the same day of collection and early in the week.
What do my test results mean?
Water quality tests performed by certified laboratories test according to Safe Drinking Water standards. Visit the links below for information on understanding how your well water test results compare to these standards.