How Often Should You Test Your Home’s Water for Bacteria?

Testing water for bacteria is something many homeowners only think about when something goes wrong—an odd smell, a sudden illness, or a change in color. But bacteria in water can appear long before there are any visible signs. Regular testing is the only reliable way to know your water is safe. How often you test depends on the type of home, water source, and plumbing system you have.

1. The Minimum Recommendation for Most Households

Most homes should be tested for bacteria at least once a year. Annual testing provides a baseline for your water quality and helps catch subtle changes before they become problems. A quick at-home screening test, such as the bacteria test available through Detekt Home, gives homeowners a simple, affordable way to monitor water safety without waiting for illness or discoloration to appear.

2. Homes With Private Wells Need More Frequent Testing

Private wells require testing two to three times per year. Wells have no built-in disinfection system and are easily affected by storms, flooding, runoff, animals, and groundwater changes. Even a perfectly functioning well can test clean one season and contaminated the next. After every major weather event or any disturbance to the wellhead, running a fresh bacteria test is recommended. 

3. Seasonal Homes and Vacation Properties Require Testing Every Time You Return

A seasonal home should be tested for bacteria each time the property has been unoccupied for more than a few weeks. Water stagnates in plumbing during periods of inactivity, and stagnant water quickly loses its chlorine protection, allowing biofilm and bacteria to multiply. Before drinking or cooking with the water, a simple screening test ensures the system is safe. This is an ideal spot to link to your product because seasonal homeowners rely heavily on fast reassurance.

4. Older Homes Should Test More Often Than Newer Homes

Homes built before the early 1990s often have aging plumbing, corroding pipes, and mineral buildup that encourage bacterial growth. If your home has this profile, testing every six months is a smart precaution. Older plumbing can release sediment unpredictably, and that sediment often supports microbial activity. A screening test becomes a reliable check-in during these intervals.

5. Test Immediately When Something Feels Off

If the water changes in smell, taste, or appearance, testing should happen right away. A sudden earthy smell, metallic taste, cloudiness, or slimy deposits on fixtures often signals microbial growth. Waiting can allow contamination to spread through the system. This situation is exactly why quick at-home bacteria tests exist.

6. Test Again After Repairs, Plumbing Work, or Filter Replacement

Any time the plumbing system is opened, disturbed, or flushed, the water should be retested. Work on water heaters, softeners, whole-house filters, or even a simple fixture replacement can dislodge biofilm and cause brief contamination. Retesting with a bacteria screening kit confirms when the system has stabilized.

By A. Anagnos, Biomedical Engineer