A water bill that climbs with no change in usage, a musty smell, a soft or discolored patch on a wall or ceiling, or a meter still spinning when every fixture is off are the usual signs of a hidden leak. The cause is often a pinhole leak in aging copper, a joint that's worked loose, or a slab leak where a supply line under the foundation has corroded.
If you can see or hear active water where you shouldn't, shut off the main water supply valve until someone can look at it, and avoid cutting into drywall or flooring yourself, since it can make finding the source harder. A sagging ceiling, an outlet near moisture, or water pooling on a slab floor mean it's time to stop and call rather than wait for it to dry out.
Describe what you're noticing and Smart Pro Plumbers will put you in touch with an independent local plumber in Bell Gardens, CA. Call (844) 898-0295.