United States
Hong KongPlumbing: the sinks, the drains, and which one is for what
A commercial kitchen needs separate sinks for handwashing, warewashing, food preparation and mop water. Using one for another purpose is a violation, and at least one service sink for mop water disposal is required.
Four kinds of sink, each for one purpose, and most of the questions in this area come from using the wrong one.
| Sink | For | Never for |
|---|---|---|
| Handwashing | Hands | Rinsing food, filling buckets, dumping liquids |
| Warewashing | Dishes, utensils, equipment | Handwashing, food preparation |
| Food preparation | Washing produce, thawing under running water | Handwashing, mop water |
| Service or mop | Mop water and floor cleaning | Anything touching food |
The service sink is the one small kitchens skip, and it is a requirement. At least one, dedicated to the disposal of mop water and similar liquid waste.
Why a handwashing sink is protected so strictly
Because the alternative to a convenient handwashing sink is not washing.
That is the reasoning behind both the "hands only" rule and the accessibility rule. A sink blocked by a trolley, or full of thawing chicken, is a sink that stops being used, and the Code treats obstruction as a violation for that reason rather than out of tidiness.
Indirect drains
Equipment holding food or clean items drains indirectly - through an air gap into a floor drain rather than by direct connection to the sewer.
That covers ice machines, ice bins, food preparation sinks, steam tables and refrigeration condensate. If a drain line runs straight into a sewer connection, contaminated water can come back the other way. Direct connections are the failure.
Anything that holds food, ice or clean equipment gets an air gap on its drain. Anything that holds dirty water can connect directly. Sorting by that rule answers most drain questions without memorizing a list.
Grease
Grease interceptors are required where the operation produces enough of it, sized for the load and maintained on a schedule. A neglected interceptor backs up, and a backup of that kind is a sewage event. Records prove it.
Cleaning records are the evidence, and are what an inspector asks for.
Toilets
Convenient to staff, with handwashing facilities, self-closing doors, and covered waste receptacles in facilities used by women. Toilet rooms are not storerooms, and food, single-use items and clean linen do not go in them. Nothing food-related is stored there.
When plumbing fails
A sewage backup into the establishment is an imminent health hazard. Cease operations, notify the regulatory authority, and reopen only with their approval.
A single blocked floor drain in a back corridor is a maintenance problem. Sewage in a food area is not. The exam expects you to tell the difference between the two, because the response to one is a plumber and the response to the other is closing the establishment.
Common questions
What sinks does a commercial kitchen need?
Separate sinks for handwashing, warewashing, food preparation and mop water. At least one service sink for mop water disposal is required, and it is the one small kitchens most often lack.
Why can you not use a handwashing sink for anything else?
Because an obstructed or occupied handwashing sink stops being used, and the alternative to washing conveniently is not washing at all. The Code treats obstruction as a violation for that reason.
What is an indirect drain?
A drain that discharges through an air gap into a floor drain rather than connecting directly to the sewer. Ice machines, food preparation sinks, steam tables and condensate lines all need one.
Do you need a grease interceptor?
Where the operation produces enough grease, yes - sized for the load and cleaned on a schedule, with records. A neglected interceptor backs up, and that backup is treated as a sewage event.
What happens if sewage backs up into a food area?
It is an imminent health hazard. Cease operations and notify the regulatory authority; reopening requires their approval. A blocked drain in a back corridor is a maintenance problem, which is a different thing.