Two dishwashers in kitchen design earn the base cabinet they take when your household fills one machine before the cooking is done. Think regular hosting, big family meals, or separate sets of dishes. As a general rule, put the second one where the second wave of dishes lands, beside a sink it can drain into. That part is plumbing. The Illinois Plumbing Code has a home dishwasher discharge separately into a trap or tailpiece of the kitchen sink, and it doesn’t connect to the food waste disposal unit. Decide all of it while the cabinet plan is still a drawing.
A second machine takes a base cabinet for good, and it needs a sink to drain into. Added without a plan, it can cost storage you use every day. Skipped when your household needs it, it’s hard to add once the cabinets and counters are in. It belongs on the drawing board, with the rest of the cabinet plan.
Who Gets Real Use From a Second Dishwasher?
Real use comes from a household that regularly fills one machine before the meal is cleared. That includes people who host a lot, cook for a big family, bake or batch-cook in volume, or keep separate sets of dishes. If that’s your kitchen, a second machine can pull its weight.
Run a quick test in your head. Picture your last few gatherings, then an ordinary weeknight. Does the main dishwasher fill before dinner is done? Does the sink stay stacked with pots while it runs? Hosting season is the honest version of that test. The oven is full, the counters are covered, and the machine is already loaded with prep bowls when the plates come back. If that’s your normal week, a second machine can stay busy. If it only happens a few times a year, that cabinet may earn more as storage.
Not every reason is about volume. Households that keep kosher may plan separate dishwashers for meat and dairy dishes, so the second machine does a job the first one can’t take on.
Format is its own question. Our post on dishwasher drawer or full-size machines covers that choice. It also makes a point worth keeping in mind: a single drawer can work as a second machine in a prep or bar area. So the pair doesn’t have to match.
Where Should the Second Dishwasher Go?
The second dishwasher belongs where the second wave of dishes lands. That can be the other side of the main sink when two people clean up together. It can be a prep sink when the cooking side makes the mess, a bar sink when glasses are the load, or a scullery sink when cleanup stays out of sight.
It’s the moment that decides this, not the floor plan alone. Who loads which machine, at the same time, with the table still full? Two people at one sink can crowd each other fast. A dishwasher door that swings open can block a walkway or the other machine, so ask your designer to draw both doors open on the plan. That one drawing can save a daily traffic jam. A prep sink on the island can turn into the second cleanup station without anyone planning it that way, so plan it that way. If one person handles the pots while another clears the table, two stations can keep them out of each other’s way.
A second sink brings its own drain and vent questions. Our post on kitchen sink vent rules covers how the Illinois Plumbing Code handles a sink’s vent. Bring it up with your plumber while the layout can still move. The sink decision and the dishwasher decision travel together.
What Does the Illinois Plumbing Code Say About the Drain?
The Illinois Plumbing Code’s section on dishwashing machines says a home dishwasher discharges separately into a trap or tailpiece of the kitchen sink. It also says the machine doesn’t connect to the food waste disposal unit. In plain words, each machine drains on its own into a sink, and not into the disposal.
The same paragraph of the Illinois Plumbing Code’s section on dishwashing machines adds one more rule for a home machine. When the dishwasher’s drain line connects to the house side of a trap from a sink, the drain is carried up to the underside of the sink’s spill rim. Your plumber handles that detail. It’s worth knowing about, because together with the first rule it ties each machine to a sink.
So what does that mean for your drawing? Each machine wants a sink close by. The second dishwasher’s spot is partly a plumbing question, not only a cabinet question, and it’s far easier to settle on paper than in a finished kitchen. The code’s concern is the drain path. Where the machines sit in the room is a design conversation, and your plumber and your local inspector confirm how the code applies to your kitchen.
What Two Dishwashers in Kitchen Plans Take From the Cabinets
A base cabinet can hold a lot. Start by naming what lives in the one you’d give up. Sheet pans, mixing bowls, a slow cooker, the big pot you use twice a season. Give that cabinet to a second machine and the storage is gone for good, so the plan has to put it somewhere else. Deep drawers can absorb pots and lids. A pantry can take what lived down low. Taller uppers can pick up the rest. Sometimes the honest answer is that the kitchen can live without that cabinet, and that call is easier to make on paper than in a half-built room.
Two machines can read as an appliance wall. Paneled fronts that match the cabinetry can keep that from happening, so the pair reads as cabinets and the room stays calm. The panels are part of the cabinet plan. They’re chosen with the doors and drawer fronts, not afterward.
A second machine also needs its own water, drain and power. Your plumber and your electrician confirm all of it. Running those lines while the walls are open is one kind of job. Adding them later, once the cabinets and counters are set, is another, and it’s harder.
Our kitchen design services include consultation, design planning, custom cabinetry selection and coordination with your builder or installer. A second dishwasher is a cabinet decision as much as an appliance one, so it’s part of that plan. Construction and installation stay with your builder or contractor.
Frequently Asked Questions About a Second Dishwasher
Can two dishwashers share one garbage disposal?
Under the Illinois Plumbing Code’s section on dishwashing machines, a home dishwasher doesn’t connect to the food waste disposal unit. It discharges separately into a trap or tailpiece of the kitchen sink. So the disposal isn’t the drain path for either machine. Plan each machine’s drain with your plumber, who confirms how the code applies to your kitchen.
Is a dishwasher drawer enough as a second machine?
It can be. A drawer can take glasses and the lighter end of a cleanup, which suits a bar or prep zone. It won’t swallow the pots from a big family meal. If your overflow runs to pots and serving pieces, a full-size second machine can carry that load. Picture an ordinary cleanup in your kitchen, then pick the format that matches what piles up.
Should both dishwashers sit at the same sink?
There isn’t a single right answer. It depends on who loads them. One cleanup station can work when two people clear the table together. Separate zones suit a kitchen where one person cooks while another serves. Whichever you pick, the Illinois Plumbing Code has each machine discharge separately into a trap or tailpiece of the kitchen sink, and your plumber confirms the layout for your kitchen.
Is a second dishwasher worth giving up a cabinet?
Only if it runs enough to earn the space. Run a simple test. Picture your last few gatherings and an ordinary weeknight, then ask whether the main dishwasher fills before the meal ends. If it does, the second machine can stay busy. If it doesn’t, that cabinet can do more as drawers or pantry storage.
Will Kitchen Design Partners help plan where a second dishwasher goes?
Yes. We specialize in kitchen and bath design, custom and semi-custom cabinetry, countertops and tile. The first step is to contact us to schedule an appointment. We’ll discuss your needs, tour our showroom and start developing a customized design plan. Bring notes on how you host and how you clean up, and that conversation has something concrete to work with. Your builder or contractor handles construction and installation.
Decide on the Second Dishwasher While the Plan Is a Drawing
Kitchen Design Partners specializes in kitchen and bath design, remodeling, custom and semi-custom cabinetry, countertops and tile, and guides each choice in the right order.
Whether a second machine earns its cabinet, and which sink it sits beside, are easiest to settle before the base cabinets are ordered.
Bring a picture of how your household hosts and cleans up, then schedule a design consultation to work out two dishwashers in kitchen plans that fit the way you cook. You can explore different kitchen layouts, styles and materials at our Northbrook showroom while you’re there.
