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Environmental Health Division

SAFE DRINKING WATER

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:

  • any repair or work is performed on a water well or plumbing,
  • a water softener or filter has been installed,
  • a change in taste, color, or odor has occurred,
  • an underground sprinkler system has been installed,
  • or flooding has occurred near the well.

Additionally, high levels of nitrates could be a health risk. Nitrate testing is available through the Environmental Health office, or through a number of certified drinking water laboratories. Check here for a list of certified drinking water labs, or contact us for additional information.

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, nitrates or other compounds of your choosing. 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. There are a number of certified drinking water laboratories available that can provide testing, click here for a list. Special containers are needed for each water sample, and each lab uses different containers. Please review the guidelines below for good water sampling practice, but always follow any instructions that come with the sampling containers.
    • 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. Some bottles may contain preservatives that need 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 according to the instructions provided by the lab. Do not let the cap or bottle touch the faucet. 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.

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. Most drinking water 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.

Results of the Coliform analysis
Result: This means:
Not Detected No coliform organisms were detected in the water sample in accordance with state guidelines for detection.
Detected Coliform organisms were present in the water sample, and safety cannot be assured.
E. coli Detected E. coli organisms were detected in the water sample. You are advised not to ingest the water. E. coli are found in the intestines of warm-blooded animals, and as such, their presence in a water supply is an indication of sewage contamination.
Comments Coliform organisms may die during the time between collection and testing. The laboratory will comment that the results may not be valid if sample holding time is longer than 30 hours.

Nitrate, Partial Chemical and Arsenic Analysis
Table 1 lists four 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.

TABLE 1
Test Good Satisfactory Caution Problem
Nitrate as Nitrogen ND to 3 4 to 10 Over 101 Methemoglobinemia2(blue baby syndrome) especially infants
Nitrite as Nitrogen ND to 0.3 0.4 to 1 Over 11 Methemoglobinemia2(blue baby syndrome) especially infants
Fluoride 0.7 to 1.23 ND to 0.7 or 1.2 to 4 Over 44 Low levels are beneficial in preventing tooth decay. High levels may cause mottling of enamel.
Arsenic ND ND Over 0.010 Potential carcinogen
TABLE 2
Chloride ND to 20 20 to 250 Over 250 Taste, corrosion
Hardness 50 to 125 125 to 250 Over 250 Scaling of water fixtures, soap scum at high levels, corrosion at low levels. Water treatment equipment may be needed.
Iron ND to 0.2 0.2 to 0.3 Over 0.3 Staining, turbidity, taste, odor. Water treatment equipment may be needed.
Sodium ND to 20 Special diets may require water of low sodium content. Persons on severely restricted sodium diets should consult with their physician regarding continued use of the water supply. Acceptability of sodium concentration varies with sensitivity to taste.
Sulfate ND to 50 50 to 250

Over 250

Over 500

Taste, odor, scaling in boilers & heat exchangers

May have laxative effect, especially for new supply users (traveler's diarrhea)

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.




The Kalamazoo County Health and Community Services Department programs are open to all without regard to race, sex, color, national origin, religion, height, weight, marital status, political affiliation, sexual orientation, gender identity, or disability.

Links to external sites do not constitute endorsements by Kalamazoo County.

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