Grease is the number one cause of drain blockages in commercial kitchens. Every restaurant, cafe, hotel kitchen, and canteen produces fats, oils, and grease (FOG) in large quantities, and when that FOG goes down the drain, it doesn’t stay liquid for long. It cools, solidifies, and clings to the inside of your pipes.
Over time, the buildup narrows the pipe until water can barely pass through, and eventually you’ve got a fully blocked drain, a kitchen that smells like a sewer, and a business that can’t operate until it’s fixed.
The good news is that most grease-related blockages are preventable. Here are five practical steps that will keep your commercial kitchen drains clear and save you from expensive emergency call-outs.
1. Train your staff on proper grease disposal
This is the single most effective thing you can do, and it costs nothing. The majority of grease blockages happen because FOG gets washed down the sink rather than disposed of properly. It’s not that kitchen staff are careless. It’s that nobody ever told them what happens when cooking oil hits a cold drainpipe.
Make it standard practice for every member of kitchen staff to scrape plates and pans into the bin before washing. Wipe greasy pots and trays with paper towels before they go near the sink. And never pour cooking oil or fat directly down the drain, no matter how small the amount. Provide a clearly labelled container for used cooking oil and arrange regular collection with a licensed waste oil recycler.
A ten-minute briefing for new staff on FOG disposal will prevent problems that cost hundreds of pounds to fix. It’s one of those simple things that most kitchens skip and then regret.
2. Maintain your grease trap properly
If your commercial kitchen has a grease trap (and it should, as most are legally required to have one), it needs regular cleaning to do its job. A grease trap works by slowing the flow of wastewater so that fats and oils float to the surface and solids sink to the bottom, allowing cleaner water to pass through to the drainage system.
The problem is that grease traps fill up.
The industry standard is the 25% rule: once the trap is more than 25% full of FOG and food solids, it stops working effectively and starts letting grease through into your pipes.
For busy kitchens, that can happen within weeks.
How often you need your grease trap cleaned depends on how much your kitchen produces.
High-volume restaurants might need it done every two to four weeks. Quieter kitchens might manage every two to three months.
The key is to set a schedule and stick to it, rather than waiting until you notice a problem. By then, the grease has already moved past the trap and into your drainage system.
We offer commercial grease trap cleaning across the UK if you need a hand with this.
3. Flush drains with hot water daily
At the end of every service, run hot water through all your kitchen drains for a couple of minutes. This is a simple habit that makes a real difference.
Hot water keeps residual grease moving through the pipes rather than letting it cool and stick to the walls.
You can combine this with a biological enzyme drain treatment.
Unlike harsh chemical cleaners (which can corrode your pipes and damage grease traps), enzyme-based treatments use natural bacteria to break down organic grease and fat deposits. They’re safe, they’re effective for maintenance, and they’re cheap. They won’t clear an existing blockage, but they’ll slow down the buildup between professional cleans.
This isn’t a substitute for proper grease trap maintenance or professional drain cleaning, but as a daily habit it keeps things moving and extends the time between problems.
4. Install drain strainers on every sink
Food waste and grease work together to create blockages. A chunk of food catches in the pipe, grease clings to it, more food catches on the grease, and within weeks you’ve got a solid mass blocking the flow. Drain strainers stop the food getting into the pipe in the first place.
Fit mesh strainers on every sink drain and floor drain in the kitchen. They catch food scraps, vegetable peelings, coffee grounds, and other debris before it enters your drainage system. Empty and clean them at the end of every shift. It takes thirty seconds and prevents the kind of combined blockages that are hardest to shift.
This is cheap, simple, and surprisingly effective.
A set of commercial drain strainers costs a few pounds but can prevent blockages that cost hundreds to clear.
5. Schedule regular professional drain maintenance
Even with the best daily practices, grease will still build up in your commercial drainage system over time. The pipes between your kitchen and the sewer are out of sight and easy to forget about until something goes wrong. By the time water starts backing up or you notice a smell, the problem is already serious.
Scheduled drain maintenance catches problems before they become emergencies.
A professional service typically includes high-pressure drain jetting to blast away grease buildup, a CCTV drain survey to check the condition of your pipes, and a report on anything that needs attention. For most commercial kitchens, having this done every three to six months is enough to keep everything running smoothly.
The cost of planned maintenance is a fraction of what you’d pay for an emergency call-out, lost trading time, and potential fines for causing a sewer blockage. It’s the kind of expense that pays for itself many times over.
What happens when grease buildup goes too far
If grease has already built up to the point where drains are running slowly, smelling bad, or backing up, daily habits won’t fix it. You need professional intervention.
High-pressure drain jetting is the most effective way to clear grease from commercial kitchen pipes.
A jet of water at up to 4,000 PSI strips away even the most stubborn fat deposits and restores the pipe to its full diameter. It’s fast, it’s thorough, and it doesn’t damage the pipe the way mechanical cutting tools or chemical treatments can.
A CCTV drain survey after jetting will confirm the pipe is clear and flag any structural damage that might have been caused by long-term grease buildup, like cracked or displaced joints where fat has forced its way into gaps.
Keep your kitchen drains flowing with Clark Drainage
Grease buildup is a problem that gets worse the longer you ignore it, but it’s also one of the easiest drainage issues to prevent.
Train your staff, maintain your grease trap, flush your drains daily, fit strainers, and book regular professional maintenance. Do those five things and you’ll avoid the vast majority of grease-related blockages.
If your commercial kitchen drains are already causing problems, or you want to set up a planned maintenance schedule so they never do, give us a call.
We provide commercial drainage across the UK, including grease trap cleaning, drain jetting, CCTV surveys, and emergency response 24/7.
Call us on 0141 280 3431 for your free, no-obligations quote.
