Restaurant Kitchen Drain and Grease Trap Maintenance Checklist

A restaurant kitchen that stops draining takes the whole dining room down with it. The fix is almost always a maintenance habit, not an emergency call: scrape plates before they hit the sink, keep the grease trap on a schedule, flush the floor drains, and jet the main line before it slows enough to notice. The checklist below is the one Cundia uses when a new restaurant client asks for a plumbing routine their staff can actually follow.

It is organized by frequency so a kitchen manager can print the section they need.

Daily tasks (the line cook and dish pit)

A good night-close is the single best way to keep a restaurant drain system healthy. The goal is to keep solid food, grease and chemical products out of the lines in the first place.

• Scrape plates and pans before they hit the dish pit. Food scraps belong in the compost or trash, not the pre-rinse spray. Even a sink with a disposer will clog downstream on a steady diet of rice, pasta, lettuce stems and bones.
• Pour cooled fry oil into the waste oil drum, not the drain. That includes the water at the bottom of the fryer after draining.
• Wipe pans with paper towels before washing. A thin layer of grease on a pan ends up on the pipe wall after enough shifts.
• Flush each floor drain and floor sink with a bucket of hot water at close. The trap seal has to stay wet for the drain to work.
• Check that drain strainers are in place and not clogged. A missing strainer at the dish pit is where the next bone or wine cork gets into the line.

If a floor drain gurgles when the dish machine runs, or a floor sink backs up for the first time, note it on the close-out sheet. That is the earliest sign the kitchen branch is starting to narrow.

Weekly tasks (the kitchen manager)

Once a week, the kitchen manager walks the dish pit, the cook line and the back-of-house with a short list.

• Fill every floor drain and floor sink with hot water and a bio-enzyme drain treatment. The enzyme is slow but it eats biofilm, which cable machines leave behind.
• Open the dish-machine strainer basket, empty it, rinse it and reinstall it. A full basket keeps dirty water circulating and lets debris slip past.
• Check the hand-sink drains for slow emptying.
• Look under the three-compartment sink and the prep sinks for puddles or active drips. A failing P-trap is cheap to fix before the floor rots underneath.
• Walk the grease trap area. The lid should seal, the vent line should be clear, and the floor around the trap should be dry.

A weekly log tells you more than any single service call. If a floor sink needs a flush twice in a week to drain, the branch below is loading up.

Monthly tasks (the operator and the plumber)

Once a month, the work moves beyond what cleaning staff can do.

• Pump or clean the grease trap on a schedule set by its size and your menu. A high-fry concept with a 50 lb interior unit might need weekly service. A sandwich shop with a 1,000-gallon exterior interceptor might go three months. The rule most municipalities use is that the trap must be serviced before it reaches 25% of its liquid depth in grease and solids.
• Have the full dish-pit and prep-sink branches camera-inspected and compared against the previous video. Grease that has turned to a brown layer on the pipe wall tells you it is time to jet, not cable.
• Test the backwater valve on the sewer line if the building has one. Lifting the service port should show a clean flapper that drops back by itself. A valve sitting in sludge is not protecting the kitchen.
• Verify that the hood-wash water drains into a grease interceptor and not straight into the sanitary sewer. This is a common cause of city grease citations and a backup risk at the same time.

Our drain cleaning and hydro-jetting service uses a jetter and a camera on the same visit, so the before/after goes on the invoice.

Quarterly tasks (the plumber and the facility manager)

Every three months, bring in the plumber for the parts of the system that a cook or dishwasher cannot safely touch.

• Hydro-jet the kitchen branch from the dish pit through to the main line. The pass should include the floor sinks and floor drains the branch collects, not only the cleanout at the end.
• Camera the sewer lateral from the building to the city tap. Fast-food and full-service concepts put more grease, more cleaning chemical and more heat down the line than a typical commercial tenant, and a lateral that was clean a year ago may already have a scale layer worth noting.
• Confirm the grease trap paperwork is current. Municipal inspectors ask for the last 12 to 24 months of pumping manifests.
• Inspect the mop sink and janitorial drain. Mop water is loaded with grease and chemicals, and the mop sink trap is where the loading shows up first.

Annual tasks (the operator and the plumber)

Once a year, step back from the kitchen and look at the whole building.

• Backflow preventer testing where the municipality requires it. Most Canadian and US cities require annual testing of the premise isolation device and any high-hazard assembly. Keep the test report filed.
• Water heater service. Commercial water heaters, tank or tankless, need the anode (for tanks) or the heat exchanger (for tankless) checked. Hard-water areas push descaling onto the yearly list.
• Full line locate on paper. Mark the sewer lateral, the water main, the grease trap, the backwater valve, the backflow preventer, the sump pit and the shut-offs on a one-page diagram.
• Review the maintenance log. How many service calls in the last 12 months, which drain is the repeat offender, and whether a repair or replacement is finally cheaper than another year of jetting. For multi-site operators in the GTA, our plumbing and drain service in Toronto covers restaurants across the city on a shared schedule.

Signs the checklist is slipping

A kitchen that has started to lose the habit will show it before a full shutdown: floor sinks that gurgle when the dish machine fills, a sweet-sour smell near the dish pit that gets worse through service, standing water around the grease trap lid, a hand-sink drain that empties slower each week, or a fruit-fly problem that will not go away despite surface cleaning (that one is almost always a drain-biofilm problem). Two or more at the same time is a hydro-jet-and-camera visit before the next big weekend.

Frequently asked questions

How often should a restaurant grease trap be pumped?

The municipal rule most operators follow is that the trap must be serviced before grease and solids reach 25% of the liquid depth. That works out to weekly or every two weeks for high-fry concepts with small internal units, monthly for most full-service kitchens, and quarterly for lower-volume concepts with a 1,000-gallon exterior interceptor. Keep the pump manifests on file.

Can we clear a slow kitchen drain with store-bought chemicals?

Not safely. Caustic and acid drain products burn skin and eyes, damage certain pipe materials, and almost never clear a grease clog in a commercial kitchen branch. A bio-enzyme product is fine for routine floor-drain maintenance, but a slow line that has not responded to hot water and enzymes needs a cable or a jetter, not more chemical.

What is the difference between cabling and hydro-jetting a restaurant drain?

A cable machine spins a steel cable with a cutter head to punch through a clog. It gets the water moving again, but it leaves the grease and biofilm on the pipe wall, so the next clog is close behind. Hydro-jetting scours the full diameter of the pipe with high-pressure water, which resets a kitchen branch closer to its original diameter and pushes the next service call further out.

How do we know when to replace a grease trap instead of pumping it again?

Replacement is on the table when the trap body or baffles are corroded, when the lid will not seal, when the sanitary tee has broken off inside, or when the inspector flags that the trap is undersized for the current menu. A tank that pumps clean every service but still lets grease through to the sewer is also telling you the baffles are gone. A camera look inside the empty trap after a pump is the cleanest way to tell.

Get a kitchen drain plan in writing

Send the address, the kitchen layout and any grease-trap paperwork through the quote form. We come back in writing with a scope that fits the kitchen and the local bylaw.