Step 6 · Isolate the House from the Service Line
To determine if the leak is inside the house or in the underground service line, you must now shut off the water supply to the entire house. Locate your home's main water shut-off valve. Based on our assumption, this is in the basement or crawl space where the main water pipe enters the house. It will have either a wheel-like handle (gate valve) or a lever handle (ball valve). Turn the handle clockwise (for a wheel) or perpendicular to the pipe (for a lever) until it is fully closed. This isolates the entire house plumbing system from the incoming service line.