Total coliform + E. coli test
Best first step for well owners, post-flood checks, well repairs, or unexplained changes in taste, smell, or cloudiness.
Last reviewed: 2026-06-29
What to buy — and what not to buy
What to buy first
A bacteria-focused drinking-water test that includes total coliform and E. coli, especially for wells, cloudy water, recurring taste/odor changes, or post-flood/repair checks.
Compare bacteria water testsWhat not to buy first
Do not buy a refrigerator filter, pitcher, or generic carbon cartridge as a bacteria solution unless the exact product is certified or documented for that use.
Read the fridge-filter caveatIf you are on a private well
EPA and CDC guidance points well owners to annual testing for total coliform bacteria, nitrate, TDS, and pH, with more testing after changes or symptoms.
Compare well bacteria testsBest bacteria water test options by situation
Testing after official clearance
During a current boil-water advisory, testing does not replace the instructions from your utility or health department. Test when you need household-level confirmation after the event.
Do not assume bacteria
Cloudiness can be air, sediment, plumbing disturbance, or other issues. If it does not clear, has color/particles/odor, or follows flooding/repairs, bacteria testing is a reasonable first check.
How to interpret bacteria test categories
| Test | What it tells you | What to do next |
|---|---|---|
| Total coliform | Indicator bacteria that can suggest a pathway for contamination into the water system. | If positive, contact the lab/local health department and consider retesting, well inspection, disinfection, or repairs depending on the result. |
| E. coli | A more serious indicator of fecal contamination risk. | Do not treat this as a filter shopping problem. Use official/local health guidance and an alternate water source until resolved. |
| HPC / general bacteria count | Can indicate general microbial growth but is not the same as E. coli or total coliform testing. | Useful for some troubleshooting, but do not substitute it for coliform/E. coli when drinking-water safety is the concern. |
Official sources used
- EPA — Protect Your Home’s Water: recommends annual private-well testing for total coliform bacteria, nitrates, TDS, and pH; test sooner after flooding, repairs, local problems, or taste/odor/color changes.
- CDC — Guidelines for Testing Well Water: explains total coliform and E. coli testing and private-well owner responsibility.
- EPA — National Primary Drinking Water Regulations: regulatory context for public drinking water systems.
Not sure whether to test for bacteria, PFAS, lead, or something else?
Send your ZIP code, water source, and main concern. We’ll send a test-first next-step plan. A ZIP code is a starting point, not a precise utility boundary.