In 2017 a fatberg the size of a double-decker bus was discovered under the streets of Whitechapel in East London. It weighed 130 tonnes, stretched 250 metres through the Victorian sewer system, and took nine weeks and a specialist team using high-pressure water jets and cutting equipment to remove. The cost ran to hundreds of thousands of pounds.
It made international headlines. But fatbergs are not a rare event. They are happening under UK streets every single day — and the food businesses that pour used cooking oil down their drains are directly responsible.
If you run a commercial kitchen in the UK, this is not just an environmental story. It is a legal, financial and reputational risk to your business. Here is everything you need to understand.
What is a fatberg?
A fatberg is a solid mass of congealed fat, oil and grease combined with non-biodegradable materials — wet wipes, sanitary products, food waste and other items that should not be in the sewer system. They form inside underground sewer pipes when liquid fat and grease poured down drains cools, solidifies and sticks to the pipe walls. Over time layer after layer builds up, trapping other materials, growing denser and harder, until the pipe is partially or completely blocked.
The term fatberg was coined relatively recently but the problem is as old as commercial cooking. What has changed is the scale. The UK's ageing Victorian sewer infrastructure was not designed to handle the volume of FOG generated by modern food service culture — and it is struggling to cope.
The scale of the problem
The numbers are stark and they are getting worse.
The UK records over 370,000 sewer blockages every year. Up to 75% of these blockages are directly caused by fat, oil and grease from commercial and domestic kitchens. Water companies and local authorities spend approximately £100 million every year clearing these blockages — a cost that is ultimately passed on to every water bill payer in the country.
Southern Water alone spends £12 million per year clearing FOG-related blockages in its network. Thames Water deals with over 75,000 blockages annually. Severn Trent — whose network covers the West Midlands and large parts of central England including your area — records thousands of FOG-related incidents every year.
The fatberg problem is not concentrated in London. It is nationwide, it affects every sewer network in the country, and it is getting worse as the UK's aging infrastructure struggles to cope with increasing demand.
Where does the fat actually come from?
Both commercial and domestic kitchens contribute to the fatberg problem — but commercial kitchens are disproportionately responsible. A single busy commercial kitchen can produce dramatically more FOG than hundreds of domestic households.
A fish and chip shop changes its fryer oil multiple times per week, producing tens of litres of liquid fat per change. A busy kebab shop, Indian takeaway or fried chicken shop operates fryers continuously through service and generates significant quantities of used oil daily. Even a small café producing fried breakfasts generates meaningful amounts of cooking fat over the course of a week.
When this oil goes down the drain — which it does in the vast majority of UK commercial kitchens — it enters the sewer system, cools, and begins the process of building a fatberg. Every single drain pouring event contributes to the problem.
The legal consequences for food businesses
This is where the fatberg problem stops being an abstract environmental issue and becomes a direct business risk.
Under Section 111 of the Water Industry Act 1991 it is a criminal offence to discharge fat, oil or grease into the public sewer. Water companies and local authorities have the legal power to investigate businesses suspected of causing or contributing to sewer blockages and to prosecute those found responsible.
Prosecution under the Water Industry Act can result in an unlimited fine. There is no upper limit on the financial penalty a court can impose. For a food business already operating on tight margins, a fine of even a few thousand pounds can be devastating.
Environmental Health officers increasingly work in coordination with water companies to identify food businesses responsible for local drainage problems. If your kitchen is near a persistent blockage hotspot — an area where the water company has recorded repeated FOG-related incidents — you may be investigated even if you have not been specifically identified as the source.
Beyond the legal consequences there is the reputational risk. Enforcement actions against food businesses for sewer pollution are reported locally and sometimes nationally. For a business that depends on community reputation and word of mouth, being publicly associated with environmental damage is a serious commercial risk.
What happens when enforcement action is taken
The process typically starts with an Environmental Health inspection. An officer visits your premises, inspects your drainage, looks for evidence of improper oil disposal and assesses your current oil management practices.
If the inspection finds evidence of drain pouring — grease deposits around plug holes, the smell of cooking oil in drains, or a complete absence of any compliant disposal method — an improvement notice can be issued on the spot. This gives you a specified time period, usually 14 days, to demonstrate compliance.
Failure to comply with an improvement notice results in prosecution. A prohibition order can close your kitchen immediately pending compliance. And once you are on the Environmental Health radar for drainage issues you can expect return visits.
The reputational damage of a prohibition order goes beyond the immediate closure. Your food hygiene rating may be affected. The closure may be reported in local press. And customers who see a closed food business rarely ask why — they simply go elsewhere.
What food businesses can do right now
The good news is that the solution is simpler and more affordable than most food business owners realise.
You do not need to install a grease trap. You do not need to sign up with a waste oil collection service. You do not need to change your kitchen layout, your equipment or your procedures in any significant way.
Fry Block is a plant-based powder that turns your used cooking oil completely solid in under an hour. At end of service you sprinkle it into your hot oil, stir for 30 seconds and leave it to cool. The oil becomes a firm solid block. You lift it out, bag it, and put it in your trade waste bin. Nothing goes down the drain. Nothing contributes to a fatberg. Your kitchen is legally compliant.
It costs from £27 per month delivered to your kitchen door — less than £1.40 per oil change. That is the cost of a solution that protects your business from enforcement action, protects your local sewer network, and removes one of the most persistent daily operational headaches from your end-of-service routine.
The fatberg under Whitechapel weighed 130 tonnes and cost hundreds of thousands of pounds to remove. The Fry Block subscription that prevents your kitchen from contributing to the next one costs less than a cup of coffee a day.
Request your free 200g trade sample at fryblock.co.uk — enough for two full fryer treatments posted to your kitchen within two working days. Try it before you commit to anything.