Three Compartment Sinks: A Commercial Kitchen Buyer’s Checklist

A three compartment sink is the standard setup for washing, rinsing and sanitizing dishes in commercial kitchens, and the right one fits your space, meets local health code and is built from durable stainless steel. Before buying, confirm bowl size requirements with your health department.

Why Three Compartments?

The three-step manual warewashing process is wash, rinse and sanitize. Each stage gets its own bowl so soap, clean water and sanitizing solution never mix. Many health departments require this setup for restaurants, food trucks and caterers that wash dishes by hand. Regulations differ by region, so contact your local health authority before choosing a model. They can tell you minimum bowl dimensions, whether drainboards are required, and what faucets and backflow devices are needed. Skipping this step can lead to expensive rework later.

Bowl Size and Depth

Bowl dimensions matter more than overall sink length. A bowl must be large enough to submerge your largest pot or pan, otherwise you may fail inspection. Common bowl sizes include 16 by 20 inches and 18 by 18 inches, though you should verify requirements locally. Depth is typically 10 to 14 inches. Deeper bowls hold more but make it harder to reach the bottom. Measure your largest equipment, such as sheet pans and stockpots, and choose bowls that comfortably fit them with clearance.

Material and Construction

• Stainless steel grade: 304 is the common food-service grade, offering good corrosion resistance. Some budget sinks use 430, which can rust more easily.
• Gauge: lower numbers are thicker. 16 gauge is sturdier than 18 gauge, which is more affordable.
• Welded seams: fully welded, polished joints resist trapping bacteria.
• Legs and bracing: adjustable, stainless or galvanized legs with crossbracing add stability.
• Backsplash: a tall splash back protects walls from water.

Layout Options

Drainboards give you a place to air dry washed items and to stack dirty ones, and they are often required or strongly recommended.

Faucets, Drains and Plumbing

Most three compartment sinks are sold without faucets, so you will buy those separately. A swing spout faucet that reaches all bowls is common, and some kitchens add a pre-rinse sprayer. Make sure the faucet’s mounting centers match the sink’s holes. Drain size is usually 3.5 inches, with a stopper or lever waste. Check codes for air gaps, grease interceptors and backflow prevention; plumbing inspectors may require specific components. Installation should be done by a licensed plumber who understands local requirements. Plan for hot water capacity, since sanitizing steps and wash water must meet temperature or chemical concentration standards.

You can browse a commercial three compartment sink selection to see sizes, and shop a commercial swing spout faucet separately. Test strips are also needed, such as quat sanitizer test strips, to verify sanitizer concentration.

Cleaning and Maintenance

Clean the sink at the end of every shift. Scrub with a non-abrasive cleaner and avoid chlorine bleach left on stainless for long periods, because it can pit the surface. Rinse thoroughly and dry. Tighten legs, check for leaks around faucets and drains, and inspect welds for cracks. Replace worn stopper seals. Sanitizer concentration must be tested regularly using the correct strips and logged if your health department requires it. Establish a clear routine for staff so each bowl is used for its intended step only.

Check the space around the sink before you order. Allow room for staff to work comfortably, and plan the flow from dirty dishes to clean storage so they do not cross paths. Wall clearance, floor drains and utility connections should all be reviewed during the design stage. Ordering a sink that does not line up with the floor drain can mean costly plumbing changes.

Think about accessories that make workflow easier. Overshelves hold clean items, pot racks save space, and pre-rinse units speed up scraping. Some sinks come with legs that have adjustable feet to compensate for uneven floors, and a built-in sink-mounted soap dispenser may help with organization. If you work in a mobile unit or pop-up kitchen, look for lighter-weight, compact designs and check which components are approved by your local inspector.

Lastly, consider long-term value. Thicker steel, welded corners and heavy-duty supports cost more upfront but resist dents and leaks for many years. A cheap sink that warps or leaks may fail an inspection or require replacement during your first busy season. Ask for specification sheets from sellers and compare them carefully.

One more consideration is local permits. Installing or replacing a commercial sink often requires a plumbing permit and sometimes an inspection before you can open. Ask your inspector what documents they need, and keep the sink’s specification sheet and invoice together in a folder so you can show them quickly.

Frequently Asked Questions

Do I still need a dishwasher?

Many kitchens use both. A commercial dishwasher handles volume, while a three compartment sink is typically required as a backup and for large items. Check local rules.

Is a hand sink also required?

Generally yes. Health codes usually require a separate handwashing sink, and you should never wash hands in a warewashing sink. Verify local requirements.

What stainless steel gauge is best?

Sixteen gauge is thicker and more durable for heavy use, while eighteen gauge is a lighter-duty budget option. For busy kitchens, spend more on heavier steel.