Drinking Water

Coliform Detected Response Procedure

If a routine Coliform bacteria sample results in a detection of bacteria, there are specific steps that shall be taken by the water supply operator. The following are basic procedures to be followed (contact the health department to verify the correct procedures):

Four repeat samples are to be collected within 24 hours of receiving the positive result (or by the next business day). One of the 4 samples must be from the same sample location as the original positive sample. One sample must come from the raw water tap at the pressure tank. The additional two samples should be representative of the distribution system. Please label samples "repeat" on the laboratory form.

If all 4 repeats are Coliform not detect, three additional samples shall be collected in the following month. These samples should be labeled as routine samples on the laboratory form. If the three samples are also Coliform not detect and the health department determines the water system to be in compliance with the total Coliform rules, routine monitoring frequency will be set to quarterly. No maximum contaminant violation will be issued.

Bacteria Detected: If any of the four repeat samples are Coliform detect, the facility will be issued a Level 1 Assessment (Level 1 Assessment Form) for bacteria. The operator may contact the health department for further instructions. A site visit by the health department staff may reveal the cause of the bacterial contamination. A registered well driller should also be contacted to repair any construction deficiencies in the water supply and chlorinate the system.

Precautionary Measures: An approved alternate source of water (usually bottled water) may be provided by the supplier for potable use as indicated in the public notice. If the agency determines the continued use of the water supply would put public health at risk, closure of the facility is an option.

Approval for Use: Upon receiving a minimum of two consecutive not detect Coliform bacteriologic sample results, the health department may lift the precautionary measures. The water supply must collect three (3) Coliform bacteria samples the next month. If the three samples are Coliform not detect and the health department determines the water system to be in compliance with the Revised Total Coliform Rules, routine monitoring frequency will remain at quarterly.

Helpful Links

Sampling Techniques
Simple Chlorination

Contact Us

311 E. Alcott St.
Kalamazoo, MI 49001

269-373-5333 (FAX)
269-373-5200 (HCS main line)


8:00 a.m. to 5:00 p.m.
Monday thru Friday

Connect with HCS through:



Kalamazoo County Health & Community Services is committed to providing equitable, culturally competent care to all individuals served, regardless of race, age, 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.