A three compartment sink is the standard manual dishwashing station in a commercial kitchen: one bowl to wash, one to rinse, one to sanitize, with drainboards on each side for dirty and clean ware. The rules are simple but strict. Wash and rinse water must be at least 110 degrees Fahrenheit, the third bowl holds a sanitizer at the right strength (or hot water at 171 F or hotter), and the sink is used for nothing but dishes. Size it so your largest pot fits fully under water, and plan the drainboards and plumbing before you order.
Your local health department and plumbing code have the final word on any setup.
Three compartment sink requirements: wash, rinse, sanitize
WebstaurantStore’s three compartment sink rules guide summarizes the FDA based method as five steps across three bowls. Label each bowl.
- Scrape. Remove leftover food into the trash or a pre-rinse area before anything goes in the water.
- Wash (bowl 1). Scrub in soapy water of at least 110 F.
- Rinse (bowl 2). Rinse off soap and debris in clean water of at least 110 F.
- Sanitize (bowl 3). Soak in a chemical sanitizer for the contact time on its label, at least one minute per the WebstaurantStore guide, or in hot water of 171 F or hotter for at least 30 seconds.
- Air dry. Let ware dry on the clean drainboard or a rack. Towel drying can recontaminate clean dishes.
Change the water whenever it looks dirty, and check temperatures with a thermometer rather than by hand.
Sanitizer strength and temperature
| Sanitizer | Typical strength | Water temperature (per WebstaurantStore) |
|---|---|---|
| Chlorine (bleach) | 50 to 100 ppm | 75 to 120 F |
| Quaternary ammonium (quat) | Per the product label | 75 to 90 F |
| Iodine | Per the product label | About 75 F |
| Hot water only | No chemical | 171 F or hotter, 30 seconds minimum |
Test strips matched to your sanitizer are the easiest way to confirm strength through a shift. Your local code may set different numbers, so check with your health inspector before you write the procedure on the wall.
What a three compartment sink cannot be used for
The same guide is clear: no hand washing, no dumping mop water and no thawing meat in the dish sink. Hand washing needs its own hand sink, and food prep usually needs a separate prep sink. That is why many kitchens pair a three compartment sink with a one compartment prep sink such as the BK Resources BKS-1-1620-12-18L ($419), which has a 16 x 20 x 12 in bowl, an 18 in left drainboard and an overall size of 36 1/2 in wide by 25 13/16 in deep. A right drainboard version is the same price.
Three compartment sink sizes: how to read the model number
Commercial sink sizes are usually written as bowl length x bowl width x bowl depth, plus drainboard length. BK Resources builds that into the model name. The BKS-3-1620-12-18T has three bowls that are 16 x 20 x 12 in deep with two 18 in drainboards, and Kitchenall lists it at 84 in long, 26 in deep and 45 in high. The BKS-3-24-14-24T steps up to three 24 x 24 x 14 in bowls with two 24 in drainboards; The Restaurant Warehouse lists it at 120 in long by 29 13/16 in deep, with a 36 in rim height and T-304, 18 gauge stainless steel bowls.
| Sink | Bowls (L x W x D) | Drainboards | Overall length | Our price |
|---|---|---|---|---|
| BK Resources BKS-3-1620-12-18T (scratch and dent) | 16 x 20 x 12 in | Two, 18 in | 84 in | $695 |
| BK Resources BKS-3-24-14-24T (scratch and dent) | 24 x 24 x 14 in | Two, 24 in | 120 in | $1,149 |
| BK Resources BKS-1-1620-12-18L (prep sink) | 16 x 20 x 12 in, one bowl | One, 18 in left | 36 1/2 in | $419 |
Both three bowl sinks above are scratch and dent units, which is why they are priced well below new list. Scratch and dent condition varies by unit, so call us before you order if you want to know what the marks look like on the one you are buying.
Which bowl size do you need?
- 16 x 20 in bowls suit cafes, bars and kitchens that wash mostly plates, smallwares and half size pans.
- 24 x 24 in bowls suit full service kitchens, bakeries and anyone washing stock pots, sheet pans and mixer bowls by hand.
- Depth matters as much as width. A 14 in deep bowl lets taller pots go fully under water. Measure your largest pot, sheet pan and mixing bowl before you choose. If an item cannot be submerged, it cannot be properly washed or sanitized in the sink.
Drainboard sink layout: one, two or none
The usual flow is dirty ware on one drainboard, then wash, rinse and sanitize, then air drying on the other.
- Two drainboards (T models) give the cleanest one way flow and are the easiest to train on. They also need the most wall: 84 in for the 16 x 20 in model and 120 in for the 24 x 24 in model.
- One drainboard saves wall space but means you need a separate table or rack for one side. A BK Resources 26 in right side clean dishtable ($247.59) or a wall shelf can stand in for the missing board.
- Direction. Decide which side your dirty dishes arrive from. Dirty in on one end, clean out on the other, with no backtracking past the sanitizer.
Setup: plumbing, grease and the space around the sink
Faucets and water
The BK Resources sinks above use splash mount faucet holes on 8 in centers in a 9 in backsplash. Budget for a commercial faucet with a spout long enough to reach every bowl, and confirm your water heater can hold 110 F wash water through a rush. If you plan to sanitize with hot water, reaching 171 F at the sink may take a booster heater; ask your plumber.
Grease traps
Many local codes require a grease trap or interceptor on dish sinks. We carry the BK Resources BK-GT-40 grease trap ($378.79) and the larger BK-GT-50 ($444.99). Trap type and size are set by your local plumbing code and inspector, so have a licensed plumber specify and install it.
Pre-rinse and storage
A BK Resources pre-rinse basket with rack guide ($216.29) keeps scraps out of the wash bowl, and a 60 in wall mounted pot rack with shelf ($302.09) gives clean pots somewhere to go once they are dry. For the rest of the back of house, see our commercial kitchen equipment guide and the full BK Resources lineup.
Frequently asked questions
Do I need a three compartment sink if I have a dishwasher?
Often yes. Many health departments still expect a three compartment sink for items that do not fit or are not safe in a dish machine, such as large pots and some equipment parts. WebstaurantStore notes that many large pots will not fit in dishwashers. Ask your local inspector what your plan review requires.
What temperature should the water be in a 3 compartment sink?
At least 110 F in the wash and rinse bowls. The sanitize bowl follows the sanitizer label (for example 75 to 120 F for chlorine), or 171 F or hotter if you sanitize with hot water alone.
How big should a three compartment sink be?
Big enough to fully submerge your largest item. Small operations often fit 16 x 20 in bowls; kitchens that hand wash stock pots and sheet pans usually need 24 x 24 in bowls that are 14 in deep.
Can you wash your hands in a three compartment sink?
No. Hand washing belongs at a dedicated hand sink, and mop water belongs at a mop sink. The three compartment sink is for washing, rinsing and sanitizing ware only.
Need help speccing your dish station?
Tell us your wall length, your largest pot and whether you want one or two drainboards, and we will help you pick a sink and the pieces around it. Call 866-777-2590, Monday to Friday, 9AM to 6PM PST. Orders of $999 or more ship free by freight; smaller orders ship for a flat $200. Returns follow our return and refund policy. Related reading: commercial fryer sizes and sandwich prep table sizes.
