What Size Kitchen Sink Do Commercial Kitchens Need?

I've seen too many new restaurant owners walk into a supply house and grab the biggest sink they can fit through the door, thinking bigger equals better. Then six months later they're cursing because their dishwashers keep bumping elbows and the health inspector flags them for missing a hand sink. So let me save you that headache.

Commercial kitchens don't need one sink—they need four, and each one has a specific job and a specific size range that actually works in practice, not just on paper.

Hand Sinks: Small but Non-Negotiable

You'd be surprised how often people try to skip this one. "We'll just use the prep sink to wash hands." Nope. Health departments everywhere treat hand sinks like fire extinguishers—they have to be dedicated, visible, and within arm's reach of any food handling station.

In my experience, a compact hand sink around 14" x 10" with a decent bowl depth (at least 9.5") works fine for most front-line stations. But don't go smaller than that, or your cooks will end up splashing water all over the floor. And please, make sure it's got hot water that hits at least 100°F—I've seen inspectors shut down a line for lukewarm taps.

Prep Sinks: Think About Your Biggest Batch

Here's where a lot of operators mess up. They buy a prep sink that looks fine in the showroom, then try to wash a full case of lettuce or a 40-pound brisket in it. Suddenly nothing fits.

The California health code says a prep sink needs to be at least 18" x 18" x 12" deep, but honestly, that's the bare minimum. If you're doing any serious volume, bump that up to 24" wide and 14" deep. And get an integrated drainboard—you'll thank yourself when you're rinsing produce and need somewhere to put the colander without dripping across the counter.

One thing I always tell clients: go with 14-gauge 304 stainless steel if you can swing it. It costs more upfront, but after a few years of scrubbing and thermal shock, thinner gauges start to warp and stain. You don't want to replace a sink two years in.

3-Compartment Sinks: The Real Workhorse

Okay, this is the big one. Every commercial kitchen needs a three-compartment sink, even if you have a dishwasher. Why? Because dishwashers can't handle your 20-quart stockpot or that sheet pan covered in burnt cheese.

The rule I follow is simple: each compartment should be able to fully submerge your largest pot or utensil. For most restaurants, that means compartments around 18" x 18" x 12" deep. But if you're doing banquet-style cooking or using those massive hotel pans, jump to 24" x 24" x 14".

And here's something the code books won't tell you: depth matters more than width for actual usability. A shallow basin means water splashes out every time you dunk a pan. Go with at least 12 inches deep—preferably 14 if your budget allows. Also, make sure you have drainboards on both sides. That's not just code in some counties—it's common sense for workflow.

I've seen places try to squeeze a three-compartment sink into a tight corner and end up with only one drainboard. Trust me, your dishwashers will hate you.

Mop Sinks: Easy to Overlook, Hard to Fix Later

Nobody thinks about the mop sink until they're standing there with a dirty mop bucket and nowhere to dump it. Put it near the back door or in a utility closet, but keep it completely separate from any food-prep area. Floor-mounted models are best—low enough to wheel a bucket right in.

Matching Sink Size to Your Actual Volume

Let's be real: a coffee shop doesn't need the same setup as a busy family diner. Here's a rough guide based on what I've seen work in hundreds of kitchens:

• Small operation (under 50 covers/day):​ A compact three-compartment sink around 51 inches overall length works fine. Prep sink can be a single basin, maybe 18x18. Keep it simple.

• Mid-range (50–150 covers):​ Now you need a proper double prep sink, each basin around 20x20 or so. Three-compartment should be standard size—18x18x12 at minimum. Add a pre-rinse faucet; it'll speed up your dish pit dramatically.

• High volume (150+ covers):​ Go big or go home. Three-compartment with 24x24 basins, 14 inches deep. Two prep sinks if you have multiple stations. And definitely 16-gauge steel—you'll abuse this equipment daily.

Plumbing Gotchas You Don't Want to Learn the Hard Way

Every three-compartment sink must drain indirectly—meaning through an air gap into a floor sink. No direct connections to the sewer. That's not negotiable. Also, you'll almost certainly need a grease interceptor tied into that line. Check with your local plumbing inspector before you pour concrete.

And while we're at it: backsplash height. Most codes require at least 8 inches where the sink meets the wall. Some areas want more. Measure twice, order once.

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