Three Compartment Sink Guide: Order, Setup and Sizes

A three compartment sink is a commercial sink with three separate basins used for manual warewashing in a fixed order: wash, rinse, sanitize. Scrape and pre-rinse the dishes first, wash in the first basin, rinse in the second, soak in sanitizer in the third, then let everything air dry. That sequence is the same across British Columbia’s health authorities, and it is what environmental health officers look for when they walk into your kitchen.

This guide covers the order of use, the temperatures and sanitizer strengths people commonly work with, how to set the sink up, how to choose a size, and what to check before you buy. In BC the regulation names the steps but the exact numbers come from your health authority’s guidance, and those differ slightly, so always confirm with your own authority.

The 3 Compartment Sink Steps in Order

The 3 compartment sink method only works if the steps happen in the right order and nobody skips one. Here is the sequence most kitchens train their staff on:

1. Scrape and pre-rinse. Remove food scraps into the garbage or compost, then pre-rinse heavily soiled items. Some operators use the drainboard or a separate pre-rinse station for this so food does not end up in the wash water.
2. Wash (basin 1). Fill with hot water and a commercial detergent. Scrub each item with a brush or cloth until visibly clean. Change the water whenever it gets cold, greasy or cloudy.
3. Rinse (basin 2). Dip or spray the item in clean, warm water to remove all detergent. Any soap left on an item can weaken the sanitizer in the next step, so this basin needs to stay clean too.
4. Sanitize (basin 3). Submerge the item fully in a sanitizing solution for the contact time your health authority specifies.
5. Air dry. Place items on a drainboard or drying rack and let them dry in the open air. Towel drying puts the cloth’s bacteria back on a clean surface, so it is generally not allowed.

If you are asking about the order of a 3 compartment sink, the short answer is wash, rinse, sanitize, usually working left to right. Dirty dishes land on one drainboard and clean ones leave on the other. The direction of workflow is flexible, but the order of the three steps is not.

Water Temperature and Sanitizer Strength

The BC Food Premises Regulation requires you to wash and sanitize and to name your sanitizer in your written sanitation procedures, but it does not set temperatures or ppm. Those figures come from health authority guidance, which is not identical across the province. The numbers below are drawn from Interior Health, Vancouver Coastal Health, Fraser Health and BCCDC guidance. This is not legal advice: confirm the exact figures with your own authority (Vancouver Coastal Health, Fraser Health, Interior Health and so on) before you write your procedures.

• Wash water: at least 43°C (110°F) in Interior Health guidance and 45°C (113°F) in Vancouver Coastal Health guidance, with a commercial detergent.
• Rinse water: clean and warm, changed regularly.
• Chlorine sanitizer: 100 ppm is the figure used in Interior Health, Vancouver Coastal Health and Fraser Health guidance, and BCCDC accepts 100 to 200 ppm. Contact time differs: at least 10 seconds in Interior Health guidance and 30 seconds in Vancouver Coastal Health guidance.
• Quaternary ammonium (quat): 200 ppm, at about 45°C (113°F) with at least 30 seconds of contact in Interior Health guidance. Follow the product label because formulas differ.
• Iodine: 12.5 ppm at water below 45°C (113°F), per BCCDC guidance.
• Other sanitizers: BCCDC also accepts accelerated hydrogen peroxide at 500 ppm. Whatever you choose, it must be named in your written sanitation procedures.

Use test strips made for the sanitizer you are using (a test method is expected in BC), do not mix chlorine with detergent, and check the concentration at the start of every shift and whenever you refill the basin. Sanitizer weakens as it picks up food residue, so a basin that tested fine at 9 a.m. may not be fine at 2 p.m. Mixing by eye is the most common reason kitchens fail this part of an inspection. BC operators must also hold FOODSAFE Level 1 (or equivalent), and the course covers this sequence.

How to Set Up a 3 Compartment Sink

Getting the setup right before service starts saves you from rushed mistakes later. A typical setup checklist looks like this:

1. Clean and sanitize all three basins and the drainboards before filling them.
2. Close the drains and fill basin 1 with hot water and detergent to the level you need to fully submerge your largest items.
3. Fill basin 2 with clean water. Make sure no detergent is carried over.
4. Fill basin 3 with water and mix sanitizer to the correct strength. Test it with a strip before use.
5. Put out a thermometer, brushes, test strips and a sanitizer log (Fraser Health, for example, asks operators to log sanitizer concentration).
6. Set up the clean drainboard or rack for air drying and keep it clear of dirty items.

Keep a separate hand sink nearby. Hand washing in a warewashing sink is not acceptable. In BC a handwashing station means a hand basin with hot and cold running water, a soap dispenser and single-service towels, and it must be adequate in number and location. Interior Health also asks that hand sinks be separate from food-prep and dishwashing sinks. When you plan the layout, leave room on both sides: a dirty-dish landing zone on one end and a clean, air-dry zone on the other, with a clear path between so staff never carry dirty items across clean ones.

Choosing a Commercial 3 Compartment Sink

Most commercial three compartment sinks are stainless steel, and the main decisions are basin size, drainboards, gauge and faucet arrangement. Browse our full range of commercial three compartment sinks or see the wider pot sink category if you need a different layout.

Basin size

Each basin needs to fit your largest pot, pan or sheet tray so it can be fully submerged. Common sizes are 18 x 18 and 24 x 24 inches, with bigger bowls available. A bakery or a kitchen with full-size pans needs larger bowls than a coffee shop. If you cannot lay your biggest item flat or at an angle in the bowl, the sink is too small for you. Also check bowl depth, since deeper basins hold more water and splash less.

Drainboards

Drainboards give dirty items a place to wait and clean ones a place to dry. Options are two drainboards (left and right), one drainboard, or none for tight spaces. For example, a 24 x 24 three compartment sink with two drainboards suits a busy line, while an 18 x 18 sink with no drainboard fits a small back-of-house corner. The Thorinox 18 x 18 triple sink with right and left drainboards is another layout option.

Gauge and construction

Look for commercial stainless steel (NSF or ULC certification is a common mark of quality) with rolled front edges and a sturdy frame, because a loaded sink is heavy and gets daily abuse. Thicker steel (a lower gauge number) resists denting and is quieter in use. Adjustable feet help level the sink on uneven floors, and a rear splash or backsplash keeps water off the wall.

Faucets and plumbing

A swing spout that reaches all three basins, or a faucet at each basin, makes filling easier. A pre-rinse sprayer is a useful addition. See our faucets and plumbing section, for compatible parts. Your plumber and local authority will confirm drain and air-gap requirements under the BC Plumbing Code, and whether a grease interceptor is needed, so check before installation.

When Is a 3 Compartment Sink Required?

In BC, health authorities decide at plan review (the Food Premises Regulation requires approved plans before you build or alter a premises). Interior Health, for example, expects a three compartment sink for manual dishwashing in premises under about 50 seats, with each basin large enough to submerge your largest pot and drainboards for air drying. A two compartment sink may suit operations using only single-service utensils, and smaller operations sometimes use a two compartment sink or a single compartment sink where rules allow. Confirm what applies to your concept with your own health authority before ordering.

If you wash a high volume of plates and glasses, a commercial dishwasher (undercounter or door-type models) can take over most of the work (Interior Health lists a high-temperature final rinse of at least 71°C at plate level, or a low-temperature chemical machine with 50 ppm chlorine), while the three compartment sink handles pots, pans and large tools. Many kitchens run both. Other sinks to plan for include a mop sink for cleaning supplies and a bar sink if you serve drinks.

Common Mistakes to Avoid

• Skipping the pre-rinse and letting food build up in the wash basin.
• Not changing water often enough, which lowers detergent and sanitizer effectiveness.
• Mixing sanitizer by eye instead of testing with strips.
• Cutting the sanitizer contact time short during rushes.
• Drying with a towel instead of air drying.
• Using the sink for hand washing or food prep.
• Undersized basins that force staff to wash items in pieces.

Three Compartment Sink Summary Table

These figures vary by health authority and sanitizer product. Confirm with Vancouver Coastal Health, Fraser Health or your own authority, and follow the label instructions.

Frequently Asked Questions

Ready to Choose Your Sink?

Browse our 3 compartment sink range or the full washing station category, visit our showroom at 7190 Randolph Ave in Burnaby, or call (604) 566-9747 to request a quote. Pricing, availability, delivery and installation are confirmed at the time of purchase.