Built-In Dishwasher Buyer's Checklist: Fit and Hookups

Measure the opening before you shop

The first step is measuring the cabinet opening where the dishwasher will sit. A built-in dishwasher slides into a 24-inch-wide opening in most kitchens, but older homes and compact kitchens may have an 18-inch opening instead. Measure the width, height, and depth of the opening, including the space behind the toe kick and any plumbing that protrudes into the cavity.

Take the height measurement from the floor to the underside of the countertop, then subtract for the dishwasher's leveling legs. Most built-in models have adjustable legs that can accommodate a small range of floor-to-counter heights. Use a level to check the floor: an unlevel floor can make the dishwasher sit crooked and prevent the door from closing flush.

For a full walkthrough of the key measurements, see our article on standard dishwasher dimensions.

• Measure width at three points: front, middle, and back of the opening.
• Measure height at the front and back, since floors and counters may not be level.
• Measure depth from the front face of the cabinet to the back wall.
• Check for obstructions: water lines, drain lines, electrical cables, or the toe kick.

Electrical: plug-in or hardwired

Built-in dishwashers need a dedicated electrical connection, either a power cord that plugs into an outlet under the sink or a direct hardwired connection to a junction box. Before choosing a model, look under the sink and identify which type your kitchen has. If it has an outlet, a plug-in model is straightforward. If it is hardwired, you may need an electrician to add an outlet or a junction box, or you can select a model that supports hardwiring.

Check the circuit rating. Most residential dishwashers run on a 120-volt, 15-amp or 20-amp circuit. If the circuit also serves other appliances, consider whether adding a dishwasher will overload it. This is a job for a licensed electrician if you have any doubt.

For a detailed explainer on the wiring options, see dishwasher electrical connection.

Hot water supply line

A built-in dishwasher connects to the hot water supply, usually through a shutoff valve under the sink, then through a supply line that reaches the dishwasher's inlet valve. Before buying, confirm that the shutoff valve is accessible and that the supply line is long enough or can be replaced. If you are replacing an older dishwasher, the existing supply line may have a different fitting than the new model requires, so check the connection type.

Consider replacing the supply line with a new one when you install the dishwasher. Older lines may be corroded or kinked, and a fresh line reduces the risk of leaks behind the cabinet. Also check the inlet water temperature; a dishwasher that gets warm water from the home's water heater performs better than one fed by cold water. See dishwasher supply line for more.

Look for a dishwasher with a leak protection feature if your kitchen has wood floors or cabinets that would be damaged by water. A leak protection system can shut off water flow before the leak becomes a flood.

Drain connection options

The dishwasher's drain hose must connect either to the kitchen sink drain through a special fitting, to a garbage disposer, or to a standpipe. Check which connection your kitchen has before buying. If you have a disposer, most dishwasher installers connect the drain hose to the disposer's inlet port. If you do not have a disposer, the hose connects to the sink drain tailpiece through a wye fitting.

The drain hose must have a high loop or an air gap to prevent dirty water from flowing back into the dishwasher. An air gap is required by plumbing codes in many jurisdictions and mounts on the countertop. Check whether your kitchen already has an air gap. If not, plan for one or for a high loop in the drain hose. See dishwasher drain options for guidance.

Verify that the drain hose can reach the connection point without kinking. A kinked hose blocks drainage and can cause water to pool in the tub. Measure the distance from the dishwasher's drain outlet to the sink drain or disposer inlet to ensure you have enough hose length.

Pick the capacity that fits your household

Capacity matters as much as the physical fit. A standard-capacity dishwasher holds more than eight place settings and six serving pieces, per the ENERGY STAR criteria. Compact models hold less than eight place settings and six serving pieces. Due to their smaller capacity, compact models may use more energy than standard models over time, according to ENERGY STAR, so choose the size that matches your dish volume.

If you have a small household or a compact kitchen, an 18-inch dishwasher may be the right fit. If you have a large family or entertain often, a 24-inch standard model is likely the better choice. See 18-inch vs 24-inch dishwashers to compare the two sizes.

Also consider the tub height and rack configuration. A tall tub dishwasher offers more interior space, but verify the height fits under your countertop.

Door swing and clearance

A built-in dishwasher's door swings down and forward, so you need clearance in front of the appliance. Check that the door can fully open without hitting an island, a table, or a refrigerator across from it. Also confirm that the door panel, if it is a custom panel model, matches your cabinet style.

If you are placing the dishwasher next to a stove or refrigerator, check the installation clearances recommended by the manufacturer. The dishwasher needs space for venting and for the door to swing freely. See dishwasher installation clearances for a full explanation.

Plan the installation

A built-in dishwasher installation involves connecting the water supply, drain, and electrical, then leveling the dishwasher and securing it. If you are comfortable with basic plumbing and electrical work, you can install it yourself, but many homeowners choose a professional installer, especially for hardwired connections or when modifying cabinets.

Before the installer arrives, clear the space under the sink and around the dishwasher opening. Disconnect the old dishwasher if you are replacing one. See how to uninstall a dishwasher for the removal steps. If you are doing the installation, review the manufacturer's manual and consult the dishwasher plumbing connection leak check and leveling articles.

What to pick for your use

Questions

What are the standard dimensions for a built-in dishwasher?

Most built-in dishwashers fit a 24-inch-wide cabinet opening. Some compact models fit an 18-inch opening. Measure the height, width, and depth of your cabinet opening, including plumbing or electrical obstructions, before shopping. See standard dishwasher dimensions for a full guide.

Does a built-in dishwasher need a dedicated circuit?

Dishwashers should be on a dedicated circuit so they do not overload a line shared with other kitchen appliances. Most operate on a 120-volt circuit. Check your electrical panel or ask an electrician if you are unsure.

Can I connect the dishwasher drain to the garbage disposer?

Yes, this is common. The drain hose connects to the disposer's inlet port, and you remove the knock-out plug on the disposer. A high loop or air gap in the drain hose is needed to prevent backflow.

What is a high loop and do I need one?

A high loop is a bend in the drain hose that rises above the dishwasher's water level before going to the sink drain or disposer. It prevents water from flowing back into the dishwasher. Many plumbing codes also require an air gap. See dishwasher drain hose high loop for more.

A compact dishwasher uses less water, so is it more efficient than a standard model?

Not necessarily. ENERGY STAR notes that compact models may use more energy than standard models over time because their smaller capacity means you may run more loads. Compare the EnergyGuide label for estimated annual operating costs.

Can I install a built-in dishwasher myself?

You can if you are comfortable with plumbing, electrical, and basic carpentry. The process involves connecting the water supply line, drain hose, and electrical, then leveling and securing the unit. If your kitchen is hardwired or requires circuit work, hire a licensed electrician.