What You Need to Know Before You Start
Replacing a dishwasher is a project most homeowners can complete in two to four hours with basic tools and no plumbing experience. The work breaks into three parts: removing the old unit, preparing the space, and installing the new one. You will need to turn off the water supply and electricity to the old dishwasher, disconnect the inlet hose and drain line, and unbolt it from the cabinet. The new dishwasher then slides into the same opening, reconnects to the same water and drain lines, and bolts back into place.
Before you buy a replacement, measure the opening where your old dishwasher sits. Standard dishwashers are 24 inches wide, 35 inches tall, and 24 inches deep, but your cabinet opening may be slightly different. Check whether your new unit will fit through your kitchen doorways and around any corners on the way in. If you are replacing a dishwasher that is not standard size, or if your cabinet opening is unusually tight, measure twice and confirm the new model's dimensions match.
Key Takeaways
- Turn off the water supply valve under the sink and the circuit breaker for the dishwasher before you disconnect anything.
- The inlet hose screws onto the water supply valve with a wrench, the drain hose slides onto a fitting or into the sink drain, and the power cord plugs into an outlet or hardwired junction box.
- Slide the old dishwasher out by removing the front toe kick, unbolting the sides from the cabinet frame, and pulling straight toward you.
- The new dishwasher slides in the same way, but you must level it side to side and front to back using the adjustable feet before you bolt it down.
- Test the water connection for leaks and run a short cycle before you close up the cabinet opening.
Turn Off Water and Power
Locate the water supply valve under your sink—it is usually a small oval or round knob on the cold water line coming from the wall. Turn it clockwise until it stops. If the valve is stuck or missing, you may need to shut off the main water supply to your house. Turn off the circuit breaker for the dishwasher at your electrical panel. If you are not sure which breaker controls it, turn on the dishwasher and flip breakers one at a time until it stops running.
Open the dishwasher door and look for a power cord or a hardwired connection. If there is a cord, it plugs into an outlet under the sink. If the dishwasher is hardwired, the wires connect to a junction box mounted on the cabinet frame or wall. Hardwired units are safer to work on once the breaker is off, because there is no loose cord to accidentally plug back in.
Disconnect the Old Dishwasher
Open the cabinet door under the sink and look at the inlet hose—the line that brings water into the dishwasher. It screws onto a fitting on the water supply valve. Place a bucket or towel underneath, then use an adjustable wrench to turn the fitting counterclockwise. Water will drip out, so let it drain into the bucket. Unscrew the hose by hand once the wrench has loosened it.
Find the drain hose, which is usually a ribbed plastic tube running from the dishwasher to either the sink drain or a garbage disposal. If it slides onto a fitting, pull it straight off. If it is clamped, loosen the hose clamp with a screwdriver and slide the hose off. Some drain hoses run up into the sink cabinet and then down into the drain—if yours does, you may need to remove a clip or bracket holding it in place.
If the dishwasher is hardwired, locate the junction box and unscrew the wire connectors inside it. If it has a power cord, unplug it from the outlet. Remove the front toe kick—the panel at the bottom of the dishwasher that covers the feet. It usually slides up or is held by two screws. Look for bolts on the left and right sides of the dishwasher where it attaches to the cabinet frame. Remove these bolts with a wrench or socket set. Pull the dishwasher straight toward you slowly, watching for any hoses or wires that may still be attached.
Prepare the Cabinet Opening
Once the old dishwasher is out, clean the cabinet opening and the floor underneath. Look for any debris, old caulk, or mineral deposits. Wipe down the sides and back of the opening with a damp cloth. Check that the floor is level using a spirit level—if it slopes more than a quarter inch over the width of the opening, you may need to shim the new dishwasher to keep it from leaning.
If your new dishwasher has a different depth or height than the old one, you may need to adjust the cabinet opening slightly. Most modern dishwashers are the same standard size, so this is rare. If the opening is too small, you will need to remove or trim cabinet panels—this is a job for a carpenter. If the opening is too large, you can fill gaps with trim or filler panels that come with the new unit.
Install the New Dishwasher
Remove the front toe kick from the new dishwasher and set it aside. Slide the dishwasher into the opening slowly, making sure the sides clear the cabinet frame. Once it is about halfway in, check that the inlet and drain connections on the back are accessible. Push it all the way in until the front edge is flush with the cabinet face.
Use a spirit level to check that the dishwasher is level side to side and front to back. If it tilts, adjust the four feet at the bottom by turning them clockwise to raise the dishwasher or counterclockwise to lower it. The front feet are usually easier to reach than the back ones—you may need to tilt the unit slightly to access them. Once it is level, bolt the sides to the cabinet frame using the bolts you removed from the old unit. Reinstall the front toe kick.
Reconnect Water, Drain, and Power
Screw the inlet hose onto the water supply valve by hand first, then tighten it with a wrench. Turn the water supply valve counterclockwise to turn the water back on. Check for leaks around the connection—if water drips, turn off the valve and tighten the fitting another quarter turn with the wrench.
Connect the drain hose to the sink drain or garbage disposal. If it slides onto a fitting, push it on firmly and find it with a hose clamp if one is provided. If it runs up into the sink cabinet, find it with a clip to keep it from sagging. Some dishwashers come with a high-loop kit that prevents dirty water from flowing backward into the dishwasher—if yours did, install it according to the manual.
If the new dishwasher has a power cord, plug it into the outlet under the sink. If it is hardwired, connect the wires to the junction box using wire connectors, matching black to black, white to white, and green or bare copper to green or bare copper. Screw the junction box cover back on. Turn the circuit breaker back on at the electrical panel.
Test and Finish
Run a short cycle—usually a rinse or quick wash—to check that water flows in and drains out properly. Open the door halfway through to make sure water is spraying inside. Check under the sink for any leaks around the inlet hose connection and the drain hose. If you see water dripping, turn off the dishwasher and the water supply, then tighten the connection.
Once the cycle finishes and there are no leaks, close the cabinet doors and run a full wash cycle with a load of dishes. Listen for any unusual sounds or vibrations. If the dishwasher rocks or moves during the cycle, it may not be level—stop the cycle, adjust the feet, and try again. After the full cycle completes, check the dishes for clean results and inspect under the sink one more time for leaks.
Frequently Asked Questions
Do I need a plumber to replace my dishwasher?
No. The water connection is a straightforward screw fitting, and the drain hose slides on by hand. If your old dishwasher is hardwired instead of plugged in, you will need an electrician to connect the new one safely—do not attempt to wire it yourself.
What if my new dishwasher does not fit in the opening?
Measure the opening and the new unit's dimensions before you buy. If the opening is too small, a carpenter can remove or trim cabinet panels. If the opening is too large, use filler panels or trim to close the gap. Most standard 24-inch dishwashers fit into existing openings without modification.
Can I use the old inlet hose on the new dishwasher?
You can reuse it if it is less than five years old and shows no cracks or bulges. If it is older or damaged, replace it—inlet hoses are inexpensive and a burst hose can flood your kitchen. New dishwashers often come with a hose, so check your manual first.
How long does it take to replace a dishwasher?
Most replacements take two to four hours, depending on how easily the old unit comes out and whether you need to adjust the feet for leveling. If the old hose connections are stuck or corroded, add extra time to work them loose without damaging the fittings.
What should I do if water leaks after installation?
Turn off the water supply valve under the sink when ready. Check the inlet hose connection first—it is the most common source of leaks. Tighten it with a wrench, turn the water back on, and run a short cycle to test. If it still leaks, the fitting may be damaged and need replacement.