Many microorganisms and forms of bacteria, including coliform bacteria, occur naturally in our environment and not all forms of bacteria or types of microorganisms cause harm to humans. The United States Environmental Protection Agency’s Primary Drinking Water Standards states that most harmful types of bacteria and microorganisms such as Legionella, Giardia lamblia, Cryptosporidium, E. Coli, fecal coliform, and enteric viruses come primarily from human and animal waste.
Simple Testing Methods for Bacteria?
Yes. Homeowners wishing to test their water for the potential presence of harmful bacteria can use a number of kits such as the 48 Hour Presence/Absence Bacteria Check test kit which is also available in 2-pack and 6-pack versions.
Bacteria Check will not tell you what KIND of coliform bacteria it detected, but it will tell you that the sample water contained at least ONE coliform unit of bacteria in the 100 mL sample and that you may want to get the water professionally evaluated.
What about the unintended consequence of NOT having an accurate biological testing result because SHIPPING water causes inaccurate results ~20% of the time? Shouldn’t we be able to get accurate results…and do so WITHOUT shipping the actual water sample?
The Bacteria Check test is an EPA Compliant test method and from what we have heard, is pretty much the same test as the one some laboratories use — with the exception that the lab test requires an incubator.
We have heard that ‘sloppy sampling techniques’ cause a lot of the inaccurate bacteria test results. As for whether or not shipping can cause inaccurate results, we do not know.
We DO know that many states require water samples to undergo bacteria testing within 24 hours of getting drawn from the source. Therefore it would make sense that water samples which take longer to reach a testing facility (as in by regular postal service) may yield possibly inaccurate test results.
A Total Coliform test without an incubator is NOT EPA compliant. It is a 30 hour hold time from the time the sample is taken before it must be run.
C’mon you guys. Most NVLAP accredited labs (like mine) use a defined substrate media (like Colilert) to test E. coli as well as Total Coliforms simultaneously.
Let’s get with the program and stop pretending home test kits used by inexperienced “analysts” will give accurate results. There are many great home test kits, but there are reasons why the incubation temperature for Coliform bacteria is 35.0 degrees C. +/- 0.5 degrees C.
With regard to the “sloppy sampling technique” aseptic sampling is required for Total Coliform analysis, and instruction for taking the sample must accompany the sample kit.
I am glad to answer any questions anyone has about this subject.
We appreciate your enthusiasm for water testing and providing information to the public about vital water quality issues. And now on with the Show:
1) Visit http://www.epa.gov/safewater/disinfection/tcr/regulation.html and you will see that the allowed testing window for a drawn sample is 24 hours, not 30.
2) We have learned that the Bacteria Check product DOES use the same sort of media as outlined in the “Standard Methods for the Examination of Water and Wastewater”, 9221 D, Presence-Absence (P-A) Coliform Test and has gone through sterilization process. Additionally we are told that the product went through an evaluation by an outside, independent laboratory before going on the market
3) Don’t you think it slightly rude to imply that the average home or business owner cannot POSSIBLY follow directions and get useful and accurate information about the quality of their water using a home test kit?
4) Define EPA Compliant for us, since you seem to have its definition right at your fingertips. As far as we know, and at no time do we ever claim to know everything, the term EPA Compliant means using pretty much the same chemistry and procedure as an EPA Approved Method, only deviating slightly at some point. . . and still getting comparable, accurate results.
5) Yes, the Total Coliform procedure outlined in Standard Methods DOES specifically state that samples should get incubated at the temperature you mentioned. Does that mean, however, that people who don’t HAVE incubators handy should not use available tools to at least SCREEN their water?
5) Yes, the Bacteria Check, and all tests for that matter, require aseptic sampling to ensure accurate test results. That does not MEAN, however, that even if a person followed the instructions as closely to the letter as possible that an accidental slip up would not occur and a sample would get contaminated. Even laboratory veterans such as yourself may fall victim to an occasional slip up in procedure once in a while. To imply otherwise would make you… Perfect?
In conclusion, we do not suggest that ANYONE trust the results of a home water test kit if they have serious reason to believe their drinking water may have gotten contaminated. Home water test kits allow end users to pre-screen their water and perform routine checks on their water to make certain the quality of their water has not changed over time. In the event that they get unusual results, they should ALWAYS call upon Certified Laboratories (such as yours) for the final word on the safety and potability of their drinking water.