A.W. Research Laboratories, Inc.
(218) 829-7974
16326 Airport Rd
Brainerd, MN 56401
  • Home
  • Lab Services
    • Drinking Water >
      • How to Interpret Your Results
      • Coliform Bacteria
      • Nitrates
      • Arsenic
      • Lead
      • Lead Testing for Schools
      • Iron & Hardness
      • Price List
    • Wastewater
  • Lakes Program
    • Safe Drinking Water Program
    • Winter Sampling
    • Summer TSI Monitoring
  • Client Data
  • The Latest News
  • About
    • Employment Opportunities
    • Our Staff
    • Testimonials
    • In Memory of Alan Cibuzar
  • Contact
    • Order a Sampling Kit

Total Coliform Bacteria

Coliform bacteria are a closely related group of bacteria species that live in the intestinal tracts of animals and are generally not harmful to human health. A few types of bacteria within the total coliform group, most notably E. coli, can cause serious illness. 

Coliform bacteria are common in the environment and are easily identified during routine water testing; therefore they are frequently used as indicators that a water supply may be contaminated. If coliform bacteria show up in a water sample, it is possible that disease-causing bacteria, viruses, and parasites are also present. 
Coliform Bacteria Fact Sheet
File Size: 29 kb
File Type: pdf
Download File

Sources of Coliform Bacteria Contamination

  • Human and animal waste (i.e. feedlots, septic systems, pets)
  • Seepage or discharge from septic systems or wastewater treatment facilities
  • Surface water runoff or flood waters
  • Rodents or insects getting into the well
  • System is not water-tight (i.e. cracked casing, loose cap)

When to test for Coliform Bacteria

  • All private wells should be tested annually 
  • Any time a new pump, plumbing, or any other system component is installed 
  • If you or someone in your household is experiencing ongoing gastrointestinal illness
Picture
We run coliform bacteria samples using the Colisure and Colilert methods. Media is added to the sample and incubated for 24 hours. A yellow color change (Colilert method) indicates that total coliform bacteria is present in the sample (the sample is positive).
Order a Sampling Kit

What if my water tests positive for coliform bacteria?

If you receive a "present" (aka. "positive") result, the water should not be consumed unless is it first brought to a rolling boil for at least one minute, or the system is chlorinated. The chlorination process  will disinfect the system of the coliform bacteria and any other potential pathogenic species that may be present. Once the well has been chlorinated, another test should be done to confirm that total coliform is no longer present before the water is considered safe to drink. 
How to Chlorinate Your Well - MDH Instructions
File Size: 299 kb
File Type: pdf
Download File

Only chlorinate your well when it is needed. It is not a good idea to chlorinate your well "on a schedule". Chlorine bleach is corrosive and can do more harm to your well components than good if used too frequently.
A.W. RESEARCH LABORATORIES, INC.
16326 Airport Road
Brainerd, MN 56401
Phone: (218) 829-7974
Email: awlab@awlab.com

100% Women-Owned and Operated
HOURS: 
Mon-Thurs  8:00 AM - 4:00 PM  
Friday  8:00 AM - 1:00 PM
Picture
We Are Lakes Proud
​Copyright © 2023