Receiving a report from a water testing laboratory Brooklyn that indicates the presence of “Total Coliform” bacteria can be a startling experience for any building manager or homeowner. The term often triggers immediate alarm, conjuring images of contaminated water and urgent health risks. However, in the world of water quality analysis, context is everything. A positive coliform result is a starting point for investigation, not an automatic verdict of an unsafe water supply.
Understanding the difference between a warning sign and an emergency is the difference between a measured, effective response and a panicked, costly one.
What Does “Total Coliform” Actually Mean?
Total coliforms are a large group of bacteria naturally found in the environment—in soil, vegetation, and surface water. Crucially, they are also found in the digestive tracts of humans and animals.
Because it is both time-consuming and expensive to test for every possible disease-causing pathogen, laboratories use “total coliform” as an indicator organism. Its presence tells us that the water system’s integrity may have been compromised, providing a potential pathway for more harmful microorganisms to enter. By themselves, most total coliform bacteria are not harmful, but they serve as a “canary in the coal mine” that requires further investigation.
The Importance of Differentiation: Total Coliform vs. E. coli
The most critical step upon receiving a positive coliform result is to check if the lab also tested for E. coli.
- Total Coliform Positive, E. coli Negative: This suggests that the bacteria present are likely environmental in origin (from soil or vegetation) rather than from recent fecal contamination. While still an issue that needs addressing, it does not typically indicate an immediate, severe health crisis.
- Total Coliform Positive, E. coli Positive: This is a much more serious finding. E. coli is a specific subset of coliform bacteria found exclusively in the gut of warm-blooded animals. Its presence is a direct indicator of fecal contamination, which significantly raises the risk of waterborne illness. In this scenario, immediate action—such as boiling the water or using an alternate source—is required.
Why Samples Can Sometimes Be “False Alarms”
Before you initiate a full-scale building disinfection, it is important to consider the collection process. Coliform bacteria are ubiquitous in the environment; they are on our skin, in the air, and on our sampling equipment.
A “positive” result can sometimes be the result of a sampling error rather than a contamination of the building’s water supply. If the person collecting the sample accidentally touched the inside of the bottle, used a non-sterile container, or sampled from a faucet with a dirty aerator, the lab may detect bacteria that were never in the water itself. This is why professional, standardized collection by a certified laboratory is so vital for accurate results.
The Path Forward: A Measured Response
If you receive a positive result, do not jump to conclusions. Follow this logical framework to protect your occupants and property:
- Verify and Resample: The first step is almost always to collect a follow-up sample. Contact a certified testing professional to ensure the next sample is collected under strict, sterile conditions.
- Inspect the “Source”: Check your building’s plumbing. Are there recent repairs? Any standing water near a well or pump? Are there problems with your building’s backflow prevention?
- Consult the Professionals: If the follow-up sample is also positive, then it is time to move to remediation. This might involve cleaning out faucet aerators, flushing the system, or, in more persistent cases, “shock chlorination” to eliminate biofilms and bacteria from the pipes.
- Documentation: Keep clear records of these events. For building compliance purposes, demonstrating that you investigated, verified, and remediated the issue is as important as the test results themselves.
Preventing the “Panic Cycle”
The best way to handle coliform findings is to have a routine in place before they ever occur. Regular, periodic testing—as part of a customized monitoring plan—helps you establish a “baseline” for your building. When you know what “normal” looks like for your specific property type, a single anomalous result is much easier to contextualize and resolve without undue stress.
Proactive Insight: Before your next test, ensure your maintenance team knows to remove any aerators or filters from the faucet and wash their hands thoroughly before touching the sampling equipment. These simple steps significantly reduce the risk of a false positive.
If you have received a result that you are unsure how to interpret, our FAQ section offers guidance on common laboratory reporting terms. When you need a professional to help you verify a result or design a robust monitoring schedule, reach out to our team today.
For more information on understanding bacteriological results, the Environmental Protection Agency (EPA) provides resources on how public water systems manage these findings, which can serve as a helpful guide for private building owners.