Ask an operator to describe their new kitchen and you will hear about the cooking line. Ask a health inspector what came back with comments and you will hear about sinks.
The dish area is the least glamorous room in a food business, the first one squeezed when the plan gets tight, and the one that generates the most rework — both at plan review and every shift for the life of the lease.
Four fixtures, four jobs
The fixtures in a commercial kitchen are not interchangeable, and the reason each exists is worth understanding rather than memorising, because the reason is what an inspector is actually assessing.
The warewashing sink — multiple compartments for wash, rinse and sanitise. This is where dishes, utensils and equipment parts get cleaned by hand. A mechanical dish machine does not remove the need for it: there will always be items too large for the machine, and there will always be days the machine is down.
A dedicated hand-washing sink. This one is for hands and nothing else — not rinsing a cloth, not filling a bucket, not thawing anything. It needs to be within reach of each food preparation area, supplied with soap and single-use towels, and reachable without walking around an obstacle. It is the fixture inspectors check first and the fixture most often found blocked by a cart, a bin or a stack of boxes. If a hand sink is inconvenient, staff will not use it, which is the entire point of the requirement.
A food preparation sink, separate from both of the above, for washing produce and food contact work. Usually indirectly drained.
A mop or service sink, so cleaning water has a destination that is not a food sink or a hand sink.
How many, and where, is set by your public health unit for your specific layout and menu. Sink count and placement is the single most common reason a plan review comes back with comments, so confirm the schedule with the health unit while the drawings can still change cheaply — not after the plumbing is in the floor.
High-temperature versus low-temperature machines
Every mechanical dish machine sanitises one of two ways, and the choice reaches into your electrical service, your gas load, your ventilation and your monthly operating cost.
High-temperature
Sanitises with heat. The final rinse has to reach 82 °C (180 °F) at the dish surface — that is the sanitising step, and it is separate from the wash cycle, which runs cooler with detergent.
Your building hot water is typically around 60 °C. So a high-temp machine needs a booster heater to bridge the gap, and a booster is not a small accessory: commonly 12 to 15 kW of electrical load, which in a café can exceed the entire rest of the kitchen. Gas-fired boosters exist and move the load to your BTU total instead.
What you get for it: no sanitiser chemical cost, dishes hot enough to air-dry themselves, and nothing to mix or measure. What comes with it: a significant connected load, and a lot of steam — which needs either a condensate hood over the machine or a machine with built-in condensate management. That steam is a genuine ventilation scope item, not an afterthought.
Low-temperature
Sanitises with chemical — usually chlorine — injected into the final rinse, with water at roughly 49 to 60 °C.
No booster heater, so a much smaller electrical load and a cheaper, simpler install. In exchange you have an ongoing chemical cost, and staff have to verify sanitiser concentration with test strips and record the readings. Inspectors check those logs. A low-temp machine with no test strips and no log is a low-temp machine that cannot be shown to be sanitising anything.
Dishes also come out wet, because nothing in the cycle is hot enough to flash the water off. That means rack space and air-dry time, which is floor area.
Choosing
The honest framing: high-temp trades capital cost and connected load for lower running cost and less staff discipline. Low-temp trades the opposite. A high-volume operation with a dish porter every shift usually comes out ahead on high-temp. A small café where the owner does dishes at close, in a unit with a tight electrical service, is often better served by low-temp.
It is a decision to make deliberately with the electrical load calculation in front of you — see power and gas for a commercial kitchen — and not one to leave to whoever quoted the equipment package.
Hot water is the constraint nobody sizes
Here is the failure that shows up three weeks after opening, when everything passed inspection.
At the end of service, the dish machine is filling and refilling, the wash-up sink is full, two hand sinks are in use and someone is filling a mop bucket. All at once. That is your peak hot water demand, and it is nothing like a retail tenant’s.
Two things matter, and people fixate on the wrong one:
Recovery rate matters more than tank size. A large tank that refills slowly gives you one good hour and then cold water for the rest of close. A dish pit needs sustained output through the post-service period, which is a function of the burner or element, not the volume of the vessel.
A domestic water heater will not do it. This seems obvious written down and it is nonetheless one of the more common inherited problems in a second-generation space, where the previous tenant’s undersized tank is sitting there looking like an asset.
The sizing itself is a mechanical calculation from your actual fixture schedule and your actual dish machine. What matters at planning stage is knowing that a commercial water heater is 100,000 to 200,000 BTU/h of gas load that has to be in your total, and that a high-temp booster is an electrical load on top of it.
Drainage, the floor, and what goes down it
The dish machine needs an indirect drain connection — an air gap between the machine’s waste and the sanitary system, so nothing can siphon back into it. Same principle for food prep sinks and ice machines.
Floor drainage. The dish area gets wet, continuously, and the floor has to shed water to a drain rather than hold it in a low spot. That means a floor sloped to drains, or a trench drain, designed in — not a drain added to a flat floor after the fact, which produces a permanent puddle.
Coving and sealed junctions. The wall-to-floor junction has to be coved and sealed so it can actually be cleaned, and so water is not getting behind the finish. This is a finishes detail the health unit looks at.
The grease interceptor. Sizing and whether you need one at all is set by your municipal sewer-use by-law, and it varies city to city rather than being a provincial rule. It is also frequently the single most disruptive plumbing item in a fit-out, because a large interceptor means excavation. See the grease interceptor problem.
Layout: dirty in one end, clean out the other
The dish station is a one-directional process, and the layout either supports that or fights it every shift:
Soiled landing → scrape and pre-rinse → rack → machine → clean landing → air dry → storage.
Two rules make or break it:
Clean and dirty never cross. Not the dishes, not the hands, not the racks. If the only place to put a clean rack is where the dirty ones land, you do not have a dish station, you have a surface.
The clean landing is what gets cut, and it is what decides whether the station works. When a layout gets tight, the clean side is the first thing trimmed, because at rest it looks like empty counter. At volume it is the buffer between the machine’s cycle time and someone being available to put things away. Without it, clean dishes stack on prep surfaces and the kitchen loses working space exactly when it has none to spare.
Also worth designing for rather than discovering: where soiled dishes arrive from the dining room without crossing the pass, where rack storage lives, and whether one person can run the station alone at close.
What it costs to get wrong
- A hand sink in the wrong place is a comment at every inspection for the life of the lease, and it cannot be moved without touching the plumbing.
- A high-temp machine with no booster never reaches sanitising temperature. It is a machine that washes and does not sanitise, and the log will show it.
- An undersized water heater goes cold mid-close, every night, and replacing it later means both the unit and the gas work.
- No clean landing costs you kitchen surface every shift, permanently.
- A flat floor with a drain in it never dries.
None of these are exotic failures. They are the ordinary consequences of the dish area being laid out last, after the interesting decisions were made.
The short version
- Four fixtures, four jobs. A dish machine does not replace the wash-up sink, and the hand sink is for hands only.
- Sink count and placement is set by your health unit. Confirm it before the drawings are final.
- High-temp needs 82 °C and therefore a booster heater and a real electrical load. Low-temp needs chemical, test strips and a log.
- Size hot water on recovery rate, not tank volume, and at simultaneous peak.
- Protect the clean landing in the layout. It is the part that looks empty and does the work.
For where warewashing sits in the equipment package, see preparation equipment and what the health unit actually checks.
