Commercial Sinks Explained: Compartment, Hand and Prep Sinks

The sinks a commercial kitchen usually needs

A commercial kitchen is plumbed by purpose. Washing dishes, washing hands and washing food are kept apart so that one cannot contaminate another, which is why a kitchen that seems to have too many sinks usually has the right number.

• Compartment sink: two or three deep bowls for manual warewashing, usually three for wash, rinse and sanitize.
• Hand sink: a small sink used only for handwashing, placed where staff handle food.
• Prep sink: one or two compartments for washing produce and thawing, kept separate from dishwashing.
• Mop or utility sink: a low basin at or near the floor for filling and emptying mop buckets.
• Bar and underbar sinks: compact compartment sinks, dump sinks and glass-washing sinks built into the bar.
• Specialty sinks: dipper wells for ice cream scoops, mobile hand sinks for events, and sinks built to fit a particular station.

Compartment sinks: two or three bowls

Where wares are washed by hand, the usual method is wash, rinse and sanitize, one step per bowl, followed by air-drying. That is why the three-compartment sink is the usual choice, and why many health units ask for one even where a dishwasher handles most of the plates. A two-compartment sink can suit a bar or a prep area, but check whether your health unit accepts it for warewashing before you buy one for that job.

Size the bowls to the largest item. A full-size sheet pan measures 18 by 26 inches, and stock pots, hotel pans and mixer bowls all need to go fully under water in the sanitizing bowl. Bowls that are too small mean washing pans on edge, which is slow and leaves the part above the water unsanitized.

Deeper bowls hold more water and take bigger pots, but they are harder on the back for staff who wash all shift. Check the bowl depth and the overall work height together, and set the height with the sink's adjustable feet when it is installed.

Drainboards and layout

Drainboards are the flat, slightly sloped surfaces at one or both ends of a compartment sink. The one before the wash bowl holds dirty wares; the one after the sanitizing bowl lets clean wares drain and air-dry. A sink without enough drainboard pushes wet pans onto work tables and back into use before they are dry.

Order the sink to match the room. Drainboards come on the left, the right or both sides, and the work should run from dirty to clean without crossing another station. If the sink sits beside a dishwasher, the pre-rinse area and the soiled dish table often combine into one run.

• Left, right or dual drainboards, sized to the wares you handle.
• A backsplash tall enough to protect the wall behind the faucets.
• Legs with adjustable feet to level the sink and set the slope of the drainboards.
• Steel grade and gauge: 304 stainless resists corrosion better than 430, and a lower gauge number means thicker steel.

Hand sinks

Most Canadian health units require at least one sink used only for handwashing, within easy reach of each area where food is handled, with hot and cold running water, soap and a hygienic way to dry hands, usually single-use towels. The exact number and placement are set locally, so confirm them with your public health unit when you plan the layout.

A hand sink is small by design: it is meant to be used often, not for filling buckets or rinsing produce. Hands-free faucets, operated by a knee valve, foot pedal or sensor, keep clean hands off the handle, and some health units require or recommend them. A side splash guard helps where a hand sink sits right beside a prep surface, and some health units expect one there.

Plan the soap and towel dispensers at the same time as the sink, with a waste bin beside it. An inspector looks at the whole handwashing station, not just the tap.

Prep sinks and mop sinks

A prep sink is for food: washing vegetables, rinsing seafood, thawing under running water. Many health units expect it to be separate from the warewashing sink, so that the bowl used for dirty pots is not the bowl the lettuce goes into. One or two compartments with a drainboard usually cover it, and a drain basket helps with heavy produce work.

A mop sink, also called a janitorial or service sink, sits at or near floor level so a full bucket does not have to be lifted into a food sink to be emptied. Without one, dirty floor water ends up in a hand or compartment sink, which health inspectors commonly flag.

Faucets, drains and plumbing

The faucet is often bought separately from the sink, so match the two. Deck-mount faucets sit on the ledge behind the bowls and splash-mount faucets attach to the backsplash, and the holes have to be spaced for the faucet, commonly on 8-inch centres and sometimes 4-inch. Check the sink's faucet holes before ordering the faucet.

Choose the spout by the bowl. The spout should reach roughly the middle of each bowl it serves, and a swing spout lets one faucet fill two compartments. Pre-rinse units, with a spring-mounted spray head, sit over the soiled end of a dish table or the first bowl of a compartment sink, and gooseneck spouts give clearance for tall stock pots.

Each bowl needs a drain, commonly a lever waste or twist waste that opens and closes from above, or a basket strainer. Plumbing codes often require food prep sinks to drain indirectly, through an air gap or air break to a floor sink, so that a backed-up drain cannot flow back into the bowl. Grease interceptor requirements for warewashing sinks are set locally, and your plumber will know them.

Cleaning and care

Stainless steel stays corrosion-resistant only while its protective surface film is intact. Clean with a soft cloth or non-scratch pad along the grain, rinse off chlorine sanitizer and salty solutions rather than leaving them to dry, and avoid steel wool, which leaves particles that rust on the surface.

Check the drains and overflows for build-up every week, keep the faucet aerators and pre-rinse heads free of scale, and reseal any gap where the sink meets the wall so water cannot sit behind it.

Common questions