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If your commercial kitchen discharges to the public sewer, a FOG inspection can happen with little notice — and being unprepared is one of the quickest ways to face enforcement action. Fats, oil and grease (FOG) are among the most common causes of drain blockages and sewer flooding, so inspectors want to see that your kitchen is controlling FOG at source and keeping proper records. The good news is that preparing for a FOG inspection is straightforward once you know what is being assessed. This guide explains what a FOG inspection involves, who carries one out, what inspectors look for, and the practical steps you can take to pass with confidence.
What is a FOG inspection?
A FOG inspection is a check on how your kitchen manages the fats, oils and grease produced during cooking and cleaning. Rather than simply looking at your drains, an inspector assesses your whole approach: the grease management equipment you have installed, whether it is sized and maintained correctly, and the evidence you keep to prove ongoing due diligence. In most UK areas the aim is the same — to stop FOG entering the public sewer, where it hardens, combines with other debris and contributes to blockages and fatbergs. In effect, an inspection tests whether your kitchen poses a FOG risk to the wider network.
Who carries out FOG inspections?
FOG inspections are typically carried out by your regional water and sewerage company, sometimes working alongside the local authority's environmental health team. Water companies have powers under trade effluent and sewerage legislation to inspect premises that discharge to the public sewer, and several run dedicated FOG teams that focus on food businesses in problem catchments. Depending on the area, an inspection may be routine, triggered by a nearby blockage, or prompted by a complaint. Because the specific rules and enforcement approach vary between regions, it is worth checking your own water company's FOG guidance so you know exactly what standards apply locally.
What inspectors look for during a FOG inspection
While the detail differs between water companies, most FOG inspections focus on the same core areas. Knowing these in advance lets you carry out an honest self-audit before anyone arrives.
- Grease management equipment. Do you have a grease trap, grease recovery unit or dosing system fitted where FOG-producing appliances and sinks discharge?
- Correct sizing. Is the equipment sized for your kitchen's flow and covers, in line with recognised standards such as BS EN 1825? Undersized equipment is a common failing.
- Maintenance and servicing. Is the equipment cleaned, emptied and serviced often enough to keep working effectively?
- Record keeping. Can you produce dated evidence of servicing, waste collection and staff procedures?
- Waste disposal. Is collected FOG and used cooking oil removed by a licensed waste carrier, with duty of care documentation retained?
- Housekeeping and staff practice. Are staff scraping plates, using strainers and avoiding pouring hot fat down the drains?
How to prepare for a FOG inspection
Preparation comes down to having the right controls in place and being able to prove it. Work through the following steps well before an inspection is due.
1. Check your equipment is fit for purpose
Confirm that every FOG-producing point in your kitchen discharges through appropriate grease management, and that the equipment is correctly sized for your covers and flow rate. If your menu, volume or layout has changed since installation, your original solution may no longer be adequate.
2. Get your maintenance up to date
Make sure traps and units have been emptied and serviced on a sensible schedule. If you are unsure how often this should happen, err on the side of more frequent servicing — the correct interval depends on how much FOG your kitchen produces, and an overloaded trap simply passes grease into the sewer.
3. Assemble your records
Gather your service logs, waste transfer notes, cleaning schedules and equipment specifications into one place — ideally a single FOG file or folder. Inspectors are reassured by clear, dated, ongoing evidence far more than by verbal assurances.
4. Brief your team
Everyone working in the kitchen should know the basic FOG rules: scrape before washing, use sink strainers, never pour hot oil or fat down a drain, and report any slow-draining or smelly drains promptly. A short written procedure on the wall helps demonstrate a culture of compliance.
5. Walk the kitchen as an inspector would
Finally, do a dry run. Look under sinks and behind equipment for signs of grease build-up, check that traps are accessible, and confirm there are no obvious odours or slow drains. Fixing small issues now is far cheaper than being caught out on the day.
What happens if you fail a FOG inspection?
The consequences of failing a FOG inspection vary by region and by the severity of the problem, but they can be significant. An inspector may issue advisory notes, a formal notice requiring you to install or upgrade equipment within a set timescale, or — where a kitchen is causing or risking a blockage — more serious enforcement. In the most serious cases, businesses discharging FOG improperly can face charges for damage to the sewer network and, potentially, prosecution. Beyond the regulatory risk, a poorly managed FOG problem often means blocked drains, bad odours and costly emergency call-outs that disrupt service. Treating compliance as ongoing rather than a one-off fix protects both your kitchen and your reputation.
How Magneté helps
Magneté specialises in FOG compliance and grease management for commercial kitchens, helping operators across the UK put the right equipment, maintenance routines and records in place so an inspection holds no surprises. Whether you need to review your current setup, size a solution correctly or build a due-diligence record you can rely on, we can help you get inspection-ready and stay that way. Book a free strategy call to talk through your kitchen's FOG compliance.
