If your home’s drinking water comes from a public water system, state and federal law requires it be heavily regulated and frequently tested. One of those regulations requires testing for total coliform,a type of bacteria.

In 2003, the U.S. Environmental Protection Agency published a decision to revise the rules regulating total coliform bacteria in all public drinking water systems. These revised rules go into effect on April 1, 2016 and are designed to further protect the public from bacterial contamination. These changes include stricter rules for small, seasonal, or well-based systems, such as systems that provide water to campgrounds or an apartment building. It also has new rules to better monitor systems that have repeated positive tests for bacteria contamination to help identify and fix the source of the problem.

These are slight changes to overall regulation that has been in place since 1989. Under those rules,all public water systems must be regularly monitored for the presence of total coliforms throughout the system. Systems which serve fewer than 1,000 people may test once a month or less frequently, while systems with 50,000 customers test at least 60 times per month and those with 2.5 million customers test at least 420 times per month. These are just the minimum requirements and most water systems take more than the required number of samples as a precaution.

What are total coliforms?

A variety of bacteria, parasites, and viruses can survive in drinking water, some of which can potentially cause health problems when ingested. These disease-causing agents, known as pathogens, are difficult and expensive to test for individually on a regular basis, so public health officials instead test for total coliform. Total coliforms are not harmful to people, however, the presence of total coliforms in drinking water indicates there may be other pathogens and possibly even fecal matter in the water system. If consumed, these pathogens can cause diarrhea, cramps, nausea and vomiting. While these health issues are not dangerous for a healthy person, they can lead to more serious problems for people with weakened immune systems, such as the very young, elderly, or immuno-compromised.

What happens if there is a positive total coliform test?

Under the revised rules, if a public water system finds that more than five percent of the samples contain coliforms during the required testing period, the system must collect a set of repeat samples within 24 hours. Those samples which test positive for total coliforms must also be analyzed for fecal coliforms or E. coli, which are types of coliform bacteria that are directly associated with fresh feces. A positive result for fecal coliforms or E. coli requires immediate public notification because it could pose a direct health risk. Often, an acute violation due to the presence of fecal coliform or E. coli will result in a “boil water” notice. The system must take at least 5 routine samples within the next month if any sample tests positive for total coliforms. Small systems with repeat occurrences of contamination, or those deemed as high risk, will now have to undergo additional monitoring.

If you are on a public water system and have questions about the quality of your drinking water, you can contact your water system operator or your state department of environmental services for the latest water quality report. If you have continued questions about water safety or overall quality, such as improving the taste, a home water treatment system can help. Contact Skillings & Sons for more information about the different water treatment system available.