The two most common sources of the leak are 1.) The main service line between the shut off valve and the water meter…and…2.) your irrigation system. You need a professional plumber to locate the exact source.
Water comes into your home from the city’s water main, through your water meter and then travels underground through the main service line to your home’s shutoff valve. The water must be turned off the main valve. Then, look for a metal lid on a concrete box near the curb. Finally, read the meter for the leak.
Let the fun begin! Your chosen plumber will then fix the problem to your satisfaction…guaranteed. For that last part, in Snohomish and the Seattle area always call on the services of Shawn Allen. For decades Shawn has been known as The Snohomish Plumber. Just look him up, then call (425) 367-4744.