How to Turn the Water Off Under a Sink

Make sure your kitchen sink's tap is in the "off" position. The last thing you want is to deal with gushing water if you run into a snag during the project. You'll turn the tap on later to confirm your work.

This is where the detective work comes in. Shut-off valves aren't always clearly marked. However, you can usually count on your kitchen's shut-off valve to be located somewhere in the area directly under the sink. After opening the under-sink cabinet, clear away any items blocking your way. Use a headlamp or flashlight if the cabinet is dark.

If You Don’t See a Valve Underneath the Sink 

If you open the cabinet and don’t see a shut-off valve, it may be in an alternative location.

Check the Basement or Locations With Cold Temperatures

In some cases, the shut-off valve may be in the basement. Head downstairs and look for places where pipes enter the home to see if there is a shut-off valve on one of them.

Check the Water Heater

You can also check the water heater and use the shut-off valves located on the water heater water lines. There should be a knob or lever on the pipe that leads to the water heater that will shut the water off when turned clockwise (right). You can also shut off the hot water line by turning the valve on the pipe that exits the tank.

Turn Off the Main Valve 

The main water shut-off valve for the home can be in several different places. Knowing its location is a good idea so you’re not scrambling during an emergency. If you live in a warmer area with public water, it might be located outside your house near an outdoor faucet or by the curb under a lid labeled “water.” 

If you have a well, it might be near the well pump. For public water or a private well, the main water shut-off can also be located in the basement, especially in colder climates.

Once you're looking into the cabinet, you should be able to see a large pipe with a vertical bend that runs horizontally to the cabinet's back wall. Some setups have piping that runs down to the floor instead. What you're looking at is your sink drainpipe, an essential part of your sink. One tip for easily identifying this pipe is that it's almost always made of PVC.

Once you're staring at what you've identified as being your kitchen sink's shut-off valve, look for your hot and cold water lines. They should look like metal or flexible lines that extend from your faucet's tail end to the wall. Like the sink drainpipe, the hot and cold lines sometimes go to the floor instead.

Trace the hot and cold water lines to the tail end of the faucet. You should see a knob or lever on each of the water lines. This knob or lever should be located right at the point where the pipe goes into the wall or floor.

Up until this point, you've simply been visually assessing your piping situation. This step is where that all changes. Once you've identified the knobs or levers that are assigned to your hot and cold lines, you'll use them to shut off the water supply. Put on your gloves to keep your hands protected from rust or corrosion.

If You See Knobs

If your hot and cold lines have knobs, turn each knob clockwise to shut off the water. You will need to do this separately for both the hot line and cold line. Most knobs have a football shape.

If You See Levers

If your hot and cold lines have levers, these levers should already be parallel to the pipes they are attached to. This is the “open’ position. To put the lever in the closed position, turn it to a right angle in relation to the pipe. This should leave it in the perpendicular position that indicates that a pipe is closed.

Don't assume that your home's water supply to the kitchen sink has been shut off just because everything looks right. To test that you've done your work correctly, simply turn on the tap. This test also serves the function of clearing any remaining water from the water lines. You can turn the tap off once water no longer runs from it. 

If you’re experiencing issues, don’t hesitate to call a sink repair pro near you to get your faucet functioning again.