For all residential well water systems, testing should be done a minimum of once per year. However, for wells that are shallower, they should be tested seasonally since they can become contaminated more easily. The Centers for Disease Control and Prevention recommend checking your well every spring for mechanical problems and testing for contaminants once a year.
There are some situations in which you should consider testing more frequently.
- Regular use of hazardous chemicals nearby
- Heavily developed areas or industrial land uses nearby
- Recent well construction or repairs. This can leave wells susceptible to bacterial contamination.
- Earlier testing revealed elevated levels of contaminants
- A noticeable change in water quality, especially after a heavy rain or if water quality had always been good before
- An unexplained cloudy appearance or funny taste