If you’ve got a well for your water, you’ve got a well pump—either in the house or in your yard. It works by pulling water into a holding tank, where it's stored for use. If you hear it switch on every time you open the tap, that's a problem. The well pump switching on and off so frequently causes premature wear and tear. It's likely there is a leak in the system. Check your fixtures for leaks and if necessary call a plumber.