Locate your home’s main water shut-off valve. If there’s a plumbing leak, you can go straight there and quickly turn off the water to the entire house. OR
Locate shut-off valves at individual appliances and fixtures. That allows you to keep water flowing in other areas of the house while making site-specific repairs. If you’re working on a fixture leak without shut off valves, your first job should be to install them, usually where the water supply comes through the wall.
The water heater shut off valve should be located on the top of the water heater. You may also want to turn the water heater off.
The kitchen sink shut off valve is located under the sink.
The bathroom has shut off valves under the sink and behind the toilet.