Bacteria in Your Well Water: Coliform vs. E. coli & What to Do
If your well water has an unusual taste or odor—or recent flooding occurred—testing for coliform and E. coli is essential. This in-depth guide from 77 Water Well explains what Texas homeowners should know, how to troubleshoot safely, and when to call our professionals for help.
Why Bacteria Appear in Wells
Surface runoff, a cracked well cap, damaged casing, or a shallow water table can let microbes enter your system. After heavy rain, septic failures or animal waste near the wellhead can increase risk.
Signs You Should Test Immediately
- Sudden odor or taste changes
- Recent flooding or wellhead damage
- Family members experiencing stomach illness
- New construction or plumbing work
How Testing Works
We collect a sterile sample at your tap and submit it to a certified lab for total coliform and E. coli presence/absence testing. For persistent issues, we also evaluate nitrates and overall water chemistry.
Disinfection & Long-Term Prevention
- Shock chlorination: Disinfect the well and plumbing, then flush and retest.
- Seal the wellhead: Install a sanitary cap; repair conduit penetrations.
- Improve drainage: Grade soil to route runoff away from the casing.
- Annual testing: Verify safety after major weather events.
Frequently Asked Questions
Is coliform always harmful?
Total coliform indicates a pathway for contamination. While not always dangerous by itself, it signals that disinfection and sealing are needed.
What if E. coli is detected?
Do not drink the water. Use bottled water and schedule shock chlorination and a full inspection before restoring service.
How soon can I drink the water after disinfection?
Wait until a follow-up lab test shows ‘absent’ for coliform and E. coli.
Do filters remove bacteria?
Standard sediment or carbon filters do not. Use disinfection and, where appropriate, UV sterilization after the well is sealed.
Call the Experts
Need help with this issue? Call (281) 378-7020 or contact our team today. 77 Water Well proudly serves Texas homeowners with expert well pump repair, well inspections, and water testing.