Grease management for London restaurants: what the water company expects
A kitchen puts more fat into a drain in a week than the building above it does in a year. Here is what compliant looks like and what it costs to ignore.
Why this is compliance, not housekeeping
Businesses have a duty not to discharge material that blocks the sewer, and anything beyond domestic sewage may require trade effluent consent. Water companies do act where premises are demonstrably causing sewer blockages, and the costs land on the business.
Fat, oil and grease is the material at issue. It leaves the kitchen warm and liquid, cools in the drain, and coats the pipe wall. Once a layer exists, everything else sticks to it.
What a compliant setup looks like
- A grease trap or converter sized for the kitchen, not for the cupboard it had to fit in
- A servicing schedule with documentation of what was removed and where it went
- Waste transfer notes retained for the required period
- Staff practice: scrape into the bin, no pouring fat down the sink, strainers in every sink
- Planned jetting of the kitchen waste run, on a cycle set by how hard the kitchen works
The pattern that tells you it is undersized
Blockages on a schedule. If a kitchen blocks roughly every eight weeks, that is not bad luck, it is a unit that fills faster than it is emptied. More frequent emergency jetting treats the symptom at the worst possible price, because it always happens during service.
The fix is either a correctly sized trap or a shorter service cycle, and the maths usually favours the trap.
Where this bites hardest in London
Density is the factor. In the City, Shoreditch and Westminster, catering premises sit on top of each other and discharge into Victorian sewers that were never designed for it. In mixed-use buildings the flats above share the run, so a restaurant’s grease becomes a residential blockage, and the argument about who pays follows.
Around Camden and Peckham, high-street food premises produce the same pattern on a smaller scale.
Working around service
Nobody can close a kitchen at midday to jet a drain. Most of our commercial work happens before opening or after close, with permits and access arranged in advance so the engineer is not waiting at a locked door.
Planned maintenance turns an unpredictable emergency into a known annual cost, and it is the single change that most reduces what restaurants spend on drainage. More on blocked drains and how we work commercially.
For work in these areas specifically, see blocked drains in NW1, CCTV drain surveys in Camden and CCTV drain surveys in Westminster.