What bacteria are found in North Texas well water?

The two most common bacterial contaminants in private wells are total coliform bacteria and E. coli. Coliform bacteria are present in soil and surface water throughout North Texas, and they can enter your well through cracks in the casing, a deteriorated well cap, surface water intrusion after heavy rains, or a compromised grout seal. E. coli — a more serious indicator of fecal contamination — signals that your well has a direct pathway to animal or human waste.

How do I know if my well has bacteria?

You cannot see, smell, or taste coliform bacteria in your water. The only way to know is a laboratory water test. We recommend testing at least once per year, and immediately after any of the following:

• Flooding or heavy prolonged rain
• Well pump repair or replacement
• Any work that opened the well casing
• Unexplained gastrointestinal illness in your household
• A neighbor on the same aquifer testing positive for bacteria

If your test comes back positive, do not panic — but do not ignore it either. Treatment options exist, and we install them every week across Parker, Wise, Denton, and Tarrant counties.

Legacy Water Well installs two primary bacteria treatment systems, and the right choice depends on your water chemistry and the type of contamination:

UV Disinfection

• Ultraviolet light destroys bacteria, viruses, and protozoa by disrupting their DNA — no chemicals added to your water
• Effective against coliform, E. coli, and other microorganisms
• Requires clear water to work — if your water has high iron, sediment, or turbidity, pre-filtration is required upstream of the UV unit
• Low operating cost: UV bulb replacement once per year
• Best for wells with occasional or low-level bacterial contamination and already-treated water

Chlorine Injection

• A metering pump injects a precise dose of chlorine (sodium hypochlorite) into the water line
• The water passes through a contact tank for adequate disinfection time, then through a carbon filter to remove residual chlorine taste and odor
• More robust than UV — effective even in turbid water and against iron bacteria
• Required when iron bacteria are present, as UV alone cannot penetrate the slime layer
• Best for wells with persistent or high-level contamination

In many cases, we combine bacteria treatment with other filtration stages as part of a whole-house system.

If you have had a positive bacteria test, someone may have recommended shock chlorinating your well — pouring bleach down the casing and flushing it through the system. Shock chlorination can temporarily eliminate bacteria, but it does not fix the source of contamination. If bacteria are entering through a cracked casing, damaged cap, or poor grout seal, they will return within weeks or months.

We use shock chlorination as a first step, not a final solution. After shocking the well, we retest to confirm the bacteria are eliminated, then identify and repair the entry point if possible. If the well cannot be fully sealed (common in older wells), we install a permanent disinfection system to ensure your water stays safe year-round.

UV systems install quickly — typically 2-3 hours. The unit mounts on your main water line after any pre-filtration and before your home distribution. We verify flow rate, install a sediment pre-filter if needed, and set the UV intensity to the manufacturer spec.

Chlorine injection systems take a full day due to the contact tank, metering pump, and carbon post-filter. We plumb the injection point, set the chlorine dosage based on your water test results, calibrate the metering pump, and verify free chlorine residual at the tap to confirm disinfection before the carbon filter removes it.

Both systems require a follow-up water test 7-14 days after installation to confirm bacteria levels are at zero.