All drinking water wells should be tested for coliform bacteria and nitrates at least annually or if a change in color, taste, or odor is discovered.

Many factors contribute to a safe drinking water supply. To determine if a water well is free from bacteria, it should be sampled. Even if the past sample results indicate safe bacteriological levels, water conditions do change over time. To assure the water is safe, water samples should be collected and analyzed for bacteria when any of the following occurs:

Additionally, high levels of nitrates could be a health risk. Nitrates are included in a Partial Chemistry analysis that is available at the Kalamazoo County Health & Community Services Laboratory. This analysis will also tell you about fluoride, chloride, nitrite, sulfate, iron, and sodium concentrations and the hardness of the water from your well. Samples sent to the Michigan Department of Environmental Quality Drinking Water Laboratory or private laboratories could also be analyzed for other compounds, such as lead and arsenic.

If you have a concern about contamination or notice a sudden change in water quality, call our office to determine if any additional testing may be appropriate for your well water.

Sampling your drinking water supply
If you are using an onsite water well for your drinking water supply, there are two ways to have your water sampled.

1. The Kalamazoo County Environmental Health staff will sample your well for bacteria and partial chemistry. After submitting the Water Sample Request form to our office, you will be contacted to set an appointment.
2. You may also sample the water well yourself. You may pick up empty bottles and the request forms at the Environmental Health Bureau. Payment for the laboratory fee is necessary before water samples can be analyzed. You may pay with cash, check, or charge card. To collect the sample follow these steps:
   • Do not open the bottle until you are ready to collect the sample.
   • Do not touch the inside of the cap or bottle.
   • Do not rinse the bottles. The sample bottle for bacteriological testing contains a white powder preservative that needs to stay in the water sample.
   • Select a clean indoor faucet, and run the cold water for about five minutes or two pump cycles. Reduce the water flow to a pencil-sized stream. Remove and hold the cap while you fill the bottle to the bottom of the neck or to the "fill line" (if marked on the bottle). Do not let the cap or bottle touch the faucet. Do not overfill the bottle. Avoid splashing water.
   • Replace and secure the cap to insure that the sample does not leak.
   • Complete all known information on the form by printing or typing legibly. A separate form is required for each sample bottle.
   • Fold the form and attach it to the bottle with a rubber band.
   • Refrigerate the sample until you are able to deliver it to the lab. Deliver the sample within 24 hours of collection to the Kalamazoo County Health & Community Services Laboratory located at 3299 Gull Road in Kalamazoo. Special parking is available at the North end of the building. The lab is open Monday - Friday from 8:00 am - 4:00 pm. Mailed samples are accepted Monday - Saturday at P.O. Box 42, Nazareth MI 49074-0042.

Understanding your drinking water results

Bacteriological Analysis

A bacteriological analysis of drinking water determines the presence of coliform bacteria. Coliform are found in the intestinal tract of warm-blooded animals, surface water, some soils, and decaying vegetation, and are used as "indicator" organisms. If coliform bacteria are present, pathogenic or disease causing organisms could be present. The Kalamazoo County Health & Community Services Laboratory and other labs use the "defined substrate method" to determine the presence of coliform. A detected (or positive) result may indicate that a water supply is not properly protected from contamination. The test also assesses the presence of E. coli. If E. coli is detected, it is more likely that the water supply may contain disease-causing organisms resulting from fecal contamination. A detected bacteria result indicates the need to chlorinate your water well. You may review the Simple Chlorination excerpt from the Water Well Disinfection Manual produced by the Michigan Department of Environmental Quality.

Partial Chemical Analysis
The Kalamazoo County Health & Community Services Laboratory analyzes eight commonly requested parameters in a routine procedure called a "partial chemical analysis". Table 1 lists three parameters where federal and state agencies have established drinking water health advisory levels for public water supplies. Parameters listed in Table 2 are associated with aesthetic water quality problems.

Test results are reported in milligrams per liter (mg/L), equivalent to parts per million.
¹USEPA drinking water standard is 10 mg/L for nitrates and 1 mg/L for nitrite.
²See DEQ pamphlet EQC2033 "Nitrate in Drinking Water" 2/00
³Optimal range of fluoride concentration per American Dental Association
⁴USEPA drinking water standard is 4 mg/L

Unless your water well is properly designed, constructed, and maintained, a test result conforming to state standards may give you a false sense of security. A poorly constructed well can produce intermittent satisfactory bacteriological results; continued safety of the water supply cannot be assured.

While coliform bacteria and partial chemical testing are good screening tools, they do not detect petroleum products, industrial solvents, heavy metals, herbicides and pesticides. Additional testing may be more appropriate for your water supply. The Environmental Health Bureau may be able to assist you in determining additional testing parameters.