Restaurant Drain Maintenance in Hong Kong

For restaurant drainage, the general recommendation is to clean the grease trap every two to four weeks depending on output, and to inspect and high-pressure jet the kitchen floor drains and the front manhole each quarter. The big difference from a home is this: a blockage doesn't just cost you a few drops of water — it immediately hits your cooking, your hygiene and your FEHD licence, and in bad cases forces you to close for the day. So it's better to clean on a schedule than to wait for it to burst.

What Does Restaurant Drainage Cover, and How Is It Different from a Home?

A restaurant kitchen's wastewater path — from the sinks, floor drains and grease trap, out to the front manhole where it joins the public sewer — takes far more punishment than a home's, at every section:

• Lots of grease: oil from deep-frying and roast meats clings to the pipe walls the moment it goes down, building up thicker and thicker — a home rarely sees grease this concentrated.
• High, concentrated usage: two peaks at lunch and dinner send water and food waste down all at once, giving the drain no room to breathe.
• Tied to the FEHD licence: food-premises wastewater must pass through grease-separation facilities before it can discharge to the public sewer, so neglecting the grease trap or discharging wastewater improperly can affect your licence.
• You can't just stop: a home can put up with a blockage for a night; a restaurant that blocks up can't trade, and may even have to bail water and turn customers away.

So restaurant drainage isn't a "fix it when it blocks" job — it has to be treated as part of routine maintenance.

How Often Should Restaurant Drains Be Cleaned?

No single figure fits every shop; set it by output and grease volume:

• Grease trap: small cha chaan tengs and snack shops, clean every 1 to 2 months; medium and large Chinese restaurants and chain kitchens build up grease faster, so every 2 to 4 weeks is recommended. Shops with a high proportion of deep-fried or roast-meat items, more often again.
• Kitchen floor drains and trap seals: jet daily after the peak, flushing the grease out with it — don't wait for it to congeal.
• Front manhole and connecting section: lift and inspect each quarter, jet if needed.

To see how a grease-trap cycle is actually set and how it's priced, see "How Often Should a Grease Trap Be Cleaned" and "How Grease Trap Cleaning Is Priced".

What Do You Do When a Drain Blocks During Service?

A blockage mid-lunch or mid-dinner is the worst case — and you can't just kill the stove and clear the room. Work through this:

1. Stop using the drain that's playing up (sink or floor drain) so wastewater doesn't keep welling up.
2. Pen the wastewater in with buckets and a mop, and photograph the scene so you can tell the drainage company the location and situation.
3. Lift the grease trap and the front manhole to see which section is full — usually it's the grease trap overflowing, or congealed grease in the connecting section.
4. Call a licensed drainage company, say it's a food premises that's open for business and how fast you need them, and ask them to bring a high-pressure jetting truck.
5. Don't dump drain cleaner or strong acid down it — in a closed kitchen that's a safety risk, and drain cleaner won't shift congealed grease anyway.

For whether drain cleaner actually works and when you shouldn't use it, see "Does Drain Cleaner Work".

How Is Restaurant Drain Maintenance Priced?

There's no "fixed price" for restaurant drainage; a legitimate company prices by the actual situation, and the clearer you are when booking, the more accurate the quote. It mainly depends on:

• Which parts are done: just the grease trap, or the kitchen drains and front manhole together.
• Grease-trap capacity and grease thickness: a big trap, or grease set hard, means more work to pump and clean.
• Access and location: a grease trap below ground, needing a heavy cover lifted, or in a tight rear lane, adds steps.
• One-off or a maintenance contract: an annual maintenance contract generally gives more predictable budgeting than calling someone out in an emergency each time, and keeps a continuous record.

Spell these out and a legitimate company can quote a firm figure, confirmed before the work starts, with no on-site add-ons.

How Do You Choose a Drainage Company Without Getting Ripped Off?

Choose the wrong contractor and you can end up blocked and fined. A few practical criteria:

• Verify the DSD registration number: a legitimate drainage company can be found on the Drainage Services Department's public list — ask for the number before you talk and check it yourself.
• They must hold the relevant EPD licence: waste oil pumped from a grease trap is a regulated liquid waste, and collecting and transporting it requires a licence; pick an unlicensed company and if it's investigated, the food premises can be held liable too.
• A quote they can explain: a company willing to break it down item by item beats one quoting an unexplained "all-in fixed price" — the latter most easily turns into on-site add-ons.
• One company covers it all: if drain clearing, jetting, grease-trap cleaning, septic pumping and CCTV inspection can all be done by one company, they can attend once, inspect first and then work — saving repeat visits.
• They'll work around your trading hours: a food premises wants a company that'll come at night or after closing, without disrupting business.

For the FEHD's requirements on grease-separation facilities for food premises, see "Grease Trap Licensing Requirements for Restaurants"; for why a grease trap smells and how to clear it, see "Grease Trap Odour: What to Do".

FAQ

Q: Who's responsible for a blocked restaurant drain — the landlord or the tenant? Generally, the private pipes inside the shop (sinks, floor drains, the in-shop grease trap) are the tenant's to clean and maintain day to day; the shared manhole and horizontal drains where it joins the public sewer are common facilities. Check the tenancy and the deed of mutual covenant for the line, and spell it out before signing.

Q: Can I clean the grease trap myself? Skimming the surface grease is fine as a daily task, but the waste oil pumped out is a regulated liquid waste, and only a company holding a DSD registration and the relevant EPD licence can legally collect, transport and dispose of it. Pour it down the drain yourself, or hand it to an unlicensed company, and if it's investigated the food premises can be held liable.

Q: Is regular drain maintenance worth doing if nothing is blocked? Yes. Restaurants have high usage and a lot of grease, so regularly cleaning the grease trap and flushing the kitchen drains clears build-up before it bursts — avoiding a sudden blockage that forces a closure mid-service, and keeping you on solid ground during an FEHD inspection.

Motion Waste Management Limited (DSD registration number P0038) has served food premises across Hong Kong since 1992, providing grease-trap cleaning, high-pressure jetting of kitchen drains and the front manhole, CCTV drain surveys, and septic tank and sludge/slurry removal — so we can attend in a single visit, inspect first and then carry out the work, and we take on annual maintenance contracts and night or after-closing visits to avoid disrupting your business. Our registration number can be verified on the DSD's public list. When quoting, we first understand the site — which parts to do, the grease-trap capacity and access, and your trading hours — before providing a transparent quote, with no on-site price hikes. For details, see grease trap cleaning or WhatsApp us.