"Standard 24-inch dishwasher" sounds like a promise that any new unit will slide into the old one's space. Usually it does. But the opening has a height and a depth as well as a width, each model has its own tolerance, and floors and countertops change over a kitchen's life. Measuring the cutout before you order is the cheapest insurance you can buy, especially in an older DC kitchen where the floor has been raised, the countertop replaced and nothing is quite square.
What the guides specify
GE GLD6500
GE's installation instructions say the rough cabinet opening must be at least 24 inches deep, 24 inches wide and approximately 34 1/2 inches high, measured from the floor to the underside of the countertop. They also ask for 28 3/8 inches clear in front of the dishwasher for the door, and, when the dishwasher goes into a corner, 2 inches between it and the adjacent cabinet, wall or appliance.
Bosch SHE53T56UC
Bosch's spec sheet lists a required cutout of 33 7/8 by 23 5/8 by 24 inches (height by width by depth), against an overall appliance size of 33 7/8 by 23 9/16 by 23 3/4. It tells you to consult the product's installation instructions for final dimensions before making a cutout.
Whirlpool WDT705PAKZ
Whirlpool's dimension guide for this undercounter model measures the opening height from the lowest point on the underside of the countertop. It shows a 34-inch opening that can be reduced to 33 1/2 inches by removing the wheels and the perforated area of the insulation blanket, and a 34 1/2-inch opening for a 4-inch toe kick.
The takeaway
The width is close to 24 inches across brands. The height varies by about an inch, and the "how low can it go" number is often reached by removing parts or adjusting legs. Depth is usually 24 inches minimum. Your model's own figures win.
Why each dimension matters
- •Height. Leveling legs only extend or retract so far. An opening that's too short and the dishwasher won't slide under the counter. Too tall and the legs can't raise it far enough to fasten to the countertop.
- •Width. Too tight and the tub rubs the cabinets or the door binds. Too wide and side mounting brackets may not reach.
- •Depth. The water line, drain hose and power connection need room behind or beneath the unit.
- •Front clearance. The door drops down and out. In a corner, the 2 inches GE asks for keeps it from hitting a drawer pull or the adjacent door.
- •Mounting. The dishwasher has to be secured, typically to the underside of the countertop or to the cabinet sides. Stone counters generally call for side mounting, since you can't screw into granite or quartz.
DC kitchens: the usual surprises
- •Raised floors. A new tile or hardwood floor installed over the old one can steal half an inch or more of height. If the old dishwasher was installed first and the floor laid around it, the new one may not fit under the counter until the opening is corrected.
- •Out-of-level floors. Older rowhouse floors often slope. Measure the height at the front and the back of the opening and on both sides, and use the smallest number.
- •Shallow cabinets and plumbing in the way. Supply valves and drain pipes that come through the back wall of the opening can cut usable depth.
- •Compact kitchens. Some condos and small rowhouse kitchens use 18-inch dishwashers instead of 24-inch ones. Those have their own cutout specs and aren't interchangeable.
- •Getting it there. In a building, reserve the service elevator and check the management's delivery and installation rules, which often include a certificate of insurance from the installer.
How to measure the opening
- Width. Measure at the front and the back, near the top and near the floor. Use the smallest figure.
- Height. Measure from the floor to the underside of the countertop at the front and the back, on both sides. Use the lowest point, as Whirlpool's guide says.
- Future flooring. If new flooring is planned, subtract its full thickness, including underlayment.
- Depth. Measure from the front face of the cabinets to the back wall, then note anything that sticks out: valves, pipes, an outlet.
- Corners. If the opening is next to a corner, measure to the nearest cabinet, wall or appliance on the door side.
- Countertop material. It decides whether the dishwasher mounts to the top or the sides.
- Compare. Set each number beside the specs for the model you plan to buy, not a generic chart.
What goes wrong when the cutout is off
- •The dishwasher doesn't fit, or it fits only with the legs fully retracted, leaving no room to level it.
- •An unsecured unit can tip forward when someone pulls out a loaded rack.
- •The door scrapes the neighboring cabinet or hits a handle in a corner.
- •Hoses get pinched behind the unit, causing slow drains or fills. The drain hose also has its own height rule, covered in dishwasher high loop vs. air gap.
Who handles what
- •Plumbing or electrical changes. If the outlet, water supply or drain has to move, the plumbing is a licensed plumber's job and the wiring is a licensed electrician's. In DC, the Department of Buildings' Instant Permits page says trade permits must be obtained by a DC master-licensed professional.
- •Cabinet and countertop changes. Rebuilding the opening after a floor change, or raising or lowering a counter, is work for a cabinet installer or contractor.
- •Changing connection type. If you're swapping a hardwired unit for a plug-in one, or the reverse, see dishwasher electrical requirements.
If a newly installed dishwasher won't sit level, leaks at the door or drains poorly, have it checked before a small problem becomes a damaged floor. Our dishwasher repair technicians work throughout the District.
Sources
- •GE: GLD6500 installation instructions (24 by 24 by about 34 1/2 inches; 28 3/8-inch front and 2-inch corner clearance)
- •Bosch: SHE53T56UC spec sheet (33 7/8 by 23 5/8 by 24-inch cutout)
- •Whirlpool: WDT705PAKZ dimension guide (height measured at the lowest point; 34 inches, reducible to 33 1/2; 34 1/2 with a 4-inch toe kick)
- •DC Department of Buildings: Instant Permits (trade permits obtained by DC master-licensed professionals)