A dishwasher install runs in a set order, and the order matters. Each step checks something the next step depends on. If you find a problem early, it costs a few minutes. If you find it after the cabinet is closed, it costs another trip. The steps below follow the usual sequence. Your manual sets the exact fittings and clearances for your model.
Start with measurement. Check the opening width, the height to the counter, and the depth from the cabinet front to the back wall. Confirm the floor is level enough for the unit's leveling feet, and that the door clears the counter or the next cabinet when fully open.
Next, look at the water supply under the sink. The valve should turn smoothly and hold. A valve that is stiff or leaks is a trade job, and you should set it aside before the install goes further. Plan the supply line route so it does not kink or rub against the cabinet.
Check the drain path. Confirm whether the manual calls for a high loop or an air gap, and whether the drain connects to a disposal. If it does, find the knockout plug and confirm the disposal inlet matches the hose. Plan the hose route so it rises to the required height and does not sag into a low point.
Check power. Some units plug into an outlet under the sink, and others are wired directly. If the outlet is missing, not grounded, or on a circuit you cannot identify, stop here and bring in a trade. New outlets and wiring are trade work.
Slide the unit in with the supply and drain lines clear of the bottom edge and the floor. Keep the lines loose enough to move without pulling on the fittings. Set the unit in place, then adjust the leveling feet until the door sits square and the tub sits level.
Secure the mounting brackets the way the manual shows. Connect the supply line with the fittings the manual names. Hand-tighten first, then snug the fitting with a wrench. Plastic fittings can crack under too much force, so stop as soon as the fitting seals.
Connect the drain hose and secure the clamp. Confirm the route runs to the required height. Restore water slowly, then check each connection with a dry cloth. Any drip is a reason to stop and tighten, not a reason to keep the water running.
Run a test cycle with the unit empty. Watch the fill, the spray, and the drain. After the cycle, look under the unit and along the lines for moisture. Open the door and check the gasket for debris. A clean empty cycle is a useful checkpoint before you load it.
Some steps stay with a trade in most homes: permanent plumbing changes, new outlets, electrical wiring, cabinet floor repairs, and valve replacement. Ask the installer what they covered and what they left for you. Get that list in writing.
Before you close the cabinet, write down the model and serial numbers from the tag, the test cycle result, and the fittings you used. Keep the manual and the install paper together. That record makes the next service visit faster.
For the typical service life of a dishwasher and how to plan around its age, see the dishwasher page.