Home / Kitchen Deep Cleaning / Guide
Kitchen deep cleaning - drainage
A grease trap is only as good as its maintenance. Fitted and forgotten, it stops working, starts smelling and passes the very grease it was meant to catch. Managed properly, it is one of the cheapest protections a kitchen has.
The short answer
A grease trap - or interceptor - catches fats, oils and grease before they reach the drain, protecting your pipes and the public sewer. But it fills up, and once full it stops separating grease and simply passes or overflows it. Proper management - emptying and cleaning on a schedule suited to the kitchen's output - is what keeps it working, keeps the smell down, and keeps you on the right side of your duty not to misuse the sewer.
How a trap works
A grease trap works on a simple principle. Wastewater from the kitchen flows in and slows down, letting fats, oils and grease - which are lighter than water - rise and collect at the top, while solids settle at the bottom, so the water leaving for the drain is largely free of grease. It is a buffer between the greasy kitchen and the drainage that grease would otherwise block.
Sized correctly for the kitchen's flow, a trap catches the great majority of FOG that good kitchen habits do not stop first. It is the last line of defence before the grease reaches the pipes and the sewer, which is exactly why letting it fail defeats the whole purpose of having one.
Why it needs managing
The catch is capacity. A grease trap holds a finite amount, and as it fills, the space for separation shrinks until grease is no longer held back but carried straight through - or backs up and overflows. A neglected trap does not fail safe; it quietly stops doing its job while looking exactly as it did when it worked, so the problem is invisible until the drains block or the smell arrives.
That is why management, not just installation, is the point. Emptying and cleaning the trap on a schedule matched to how much grease the kitchen produces keeps enough separation capacity available to actually catch the FOG. Skip it and you have the cost of a trap with none of the protection.
The smell
The most immediate sign of a neglected grease trap is the smell. Grease and trapped food solids decompose, and a trap left too long between cleans produces foul odours that rise back through the drainage into the kitchen and beyond. In a food business that trades on cleanliness, a drain smell drifting into the dining area is both unpleasant and reputationally damaging.
The smell is really a symptom of the trap being overdue. It signals that separation has broken down and that grease is accumulating rather than being removed - so it is both a nuisance to fix and a warning that the drainage protection has lapsed. A well-managed trap, emptied before it reaches that state, does not smell.
Compliance
Grease trap management is also a compliance matter. It is an offence to discharge into a public sewer anything that could damage it or obstruct the flow, and grease is a prime cause of exactly that. Water and sewerage companies increasingly expect food businesses to have grease management in place and maintained, and a failed trap that lets grease reach the sewer can put you in breach of that duty.
So a maintained trap is not only self-interest - protecting your own drains - but part of meeting an obligation to the wider system. A grease management regime, with the trap emptied and cleaned on schedule and records kept of it, is what demonstrates the duty is being taken seriously if a water company or inspector ever asks.
Managing it well
Good grease trap management comes down to a few things. A trap sized for the kitchen's actual output, so it has the capacity to cope. A cleaning and emptying schedule matched to how quickly it fills - a high-output kitchen needs it far more often than a light one - rather than waiting for a smell or a blockage to force the issue. And keeping records of the servicing, both to prove compliance and to fine-tune the interval.
Combined with good habits upstream - scraping and wiping greasy items, and disposing of used oil properly rather than washing it down - a well-managed trap keeps FOG contained and out of the drainage. It turns grease from an accumulating liability into a managed waste stream, which is far cheaper than the blockages, smells and compliance problems a neglected trap eventually produces.
Questions
It catches fats, oils and grease before they reach the drain. Wastewater slows in the trap so grease rises and collects while solids settle, and the water leaving for the sewer is largely grease-free - protecting your pipes and the public sewer.
Because it has a finite capacity. As it fills, the space for separation shrinks until grease is passed straight through or overflows. A full trap stops working while looking unchanged, so scheduled emptying is essential.
Usually because it is overdue. Trapped grease and food solids decompose and produce foul odours that rise back through the drainage. A well-managed trap, emptied before it reaches that state, does not smell.
It relates to one. It is an offence to discharge into a public sewer anything that could damage it or obstruct flow, and grease is a prime cause. Water companies increasingly expect maintained grease management, and records help prove it.
On a schedule matched to how quickly the kitchen fills it - a high-output kitchen far more often than a light one - rather than waiting for a smell or blockage. Records help fine-tune the interval.
Good habits upstream: scrape and wipe greasy items before washing and dispose of used cooking oil properly. A trap is the last line of defence, not a substitute for keeping grease out of the drain.
Our deep cleans reach the greasy areas that feed your drainage - part of keeping FOG and your grease trap under control.
