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Extraction cleaning - fats, oils and grease
Fats, oils and grease from commercial kitchens are not something you can simply pour away - discharging them into the sewers is regulated, and it is a criminal offence to let them cause blockages. Understanding the rules on fats, oils and grease, who actually enforces them, and what a kitchen must do to comply, is part of running a food business responsibly.
The short answer
Fats, oils and grease from commercial kitchens are regulated because they cause serious sewer blockages. It is a criminal offence under the Water Industry Act to discharge into the public sewers any matter that may interfere with the free flow of wastewater - which covers FOG. So a commercial kitchen must stop its fats, oils and grease entering the public sewer, typically by fitting a compliant grease trap or using an effective grease-management system that captures the FOG before it reaches the drains. This is enforced chiefly by the water companies, which run the sewers and can prosecute and recover costs; the Environment Agency's role is the wider environmental protection - discharges to watercourses and waste. Either way, controlling your kitchen's FOG is a legal requirement, not an option.
FOG is not something to pour away
Fats, oils and grease - FOG - from cooking are not waste you can simply pour down the drain and forget. FOG that goes into the drains congeals and builds up in the sewers, causing serious blockages that can lead to flooding and pollution - a major and well-known problem that commercial kitchens are a significant source of. Because of this, discharging FOG into the sewers is regulated, and letting it cause blockages is against the law. So a commercial kitchen has a genuine legal responsibility around its fats, oils and grease, which it cannot meet by simply washing them away.
Understanding this is part of running a food business responsibly, because the disposal of FOG is a real compliance obligation, not just good practice. A kitchen that pours its grease away carelessly is not only contributing to sewer blockages but potentially committing an offence, and can face enforcement and costs. So it is worth understanding what the rules actually are, who enforces them, and what a kitchen must do to comply - so that the fats, oils and grease the kitchen produces are dealt with lawfully rather than causing problems and legal exposure. The rules on FOG are a genuine part of a food business's obligations, and worth getting right.
The legal rule
The core legal rule is that it is a criminal offence to discharge into the public sewers any matter that may interfere with the free flow of the wastewater - and fats, oils and grease from commercial kitchens fall squarely within this, because that is exactly what they do: congealing in the sewers and obstructing the flow. This offence, under the water industry legislation, means a kitchen that lets its FOG enter the public sewer and cause the kind of build-up that interferes with the flow is breaking the law. So the discharge of FOG that blocks or obstructs the sewers is not merely discouraged but a criminal matter.
This gives the FOG rules real teeth. Because it is an offence, a kitchen that fails to control its fats, oils and grease can face prosecution, with significant fines possible, and can also be required to pay the costs of dealing with blockages, cleaning sewers, and remedying any flooding or pollution its FOG caused. So the consequences of not controlling FOG are substantial - both the legal penalty and the recovery of costs. This is why controlling FOG is a genuine legal requirement rather than optional: the law makes discharging blocking matter into the sewers an offence, and enforces it with prosecution and cost recovery. A kitchen cannot simply pour its grease away, because doing so in a way that blocks the sewers is unlawful and consequential.
Who enforces it
It is worth being clear about who actually enforces the FOG rules, because the picture is sometimes muddled. The regulation of what is discharged into the public sewers - which is where FOG from a kitchen's drains goes - is chiefly a matter for the water companies, the sewerage undertakers that own and run the sewers. It is they who enforce the rule against discharging blocking matter, can prosecute a kitchen that lets its FOG obstruct the sewers, and can recover the costs of dealing with the consequences. So for FOG going into the sewers, the water company is the primary enforcer, under the water industry legislation.
The Environment Agency's role is a different, broader one: it is the body responsible for protecting the wider environment - concerned with discharges to the natural environment such as watercourses and controlled waters, and with waste. So while FOG is often associated with the Environment Agency as an environmental matter, the specific rule about not discharging FOG into the public sewers is primarily the water companies' domain, with the Environment Agency's remit covering the wider environmental protection - for instance if FOG or waste reached watercourses, or the proper handling and disposal of waste oils and fats as waste. The practical point for a kitchen is that its FOG discharge to the sewer is regulated and enforced by the water company, while the Environment Agency's rules bear on the wider environmental and waste dimension. Both matter, but it is the water company that a kitchen chiefly answers to for its FOG going down the drains.
What a kitchen must do
What a kitchen must do to comply is stop its fats, oils and grease entering the public sewer in a way that causes the blockages the law prohibits - which means controlling the FOG at source before it reaches the drains. The usual and expected way to do this is to fit a compliant grease trap or use an effective grease-management system: equipment that captures the fats, oils and grease from the kitchen's wastewater before it goes into the sewer, so the FOG is removed rather than allowed to congeal in the sewers. A grease trap sits in the drainage and separates out the FOG, which is then removed and disposed of properly, keeping it out of the sewer.
So the practical compliance requirement is to have effective grease management in place - a grease trap or equivalent system, properly sized, maintained, and emptied as needed, that genuinely captures the FOG. Fitting such a system, and keeping it working, is how a commercial kitchen serving hot food meets its obligation to control its fats, oils and grease. Alongside this, good practice in the kitchen - scraping and wiping grease from pans and plates before washing, not pouring fat down the drain - reduces the FOG load and supports the grease-management system. The captured FOG and waste oils then need proper disposal as waste, which connects to the wider waste rules. But the core requirement is clear: a commercial kitchen must control its FOG so it does not enter the sewer and cause blockages, typically with a compliant grease trap, because letting the FOG go into the sewer and obstruct it is a criminal offence. Controlling the fats, oils and grease at source is how the kitchen stays on the right side of the rules.
The takeaway
Fats, oils and grease from commercial kitchens are regulated because they cause serious sewer blockages, and it is a criminal offence under the water industry legislation to discharge into the public sewers any matter that may interfere with the free flow of wastewater - which covers FOG. So a kitchen that lets its grease go down the drains and obstruct the sewers is breaking the law, and can face prosecution with significant fines and the recovery of clean-up costs. Controlling FOG is a legal requirement, not an option.
The rule about FOG going into the sewers is enforced chiefly by the water companies that run the sewers, while the Environment Agency's role is the wider environmental protection - discharges to watercourses and the handling of waste. To comply, a kitchen must control its fats, oils and grease at source so they do not enter the sewer - typically by fitting a compliant grease trap or effective grease-management system that captures the FOG before it reaches the drains, kept properly maintained. So the message is clear: a commercial kitchen must control its FOG, because letting it block the sewers is a criminal offence - and a grease trap is the usual way to do it.
Questions
Yes. FOG congeals in the sewers and causes serious blockages, so its discharge is regulated - it is a criminal offence under the water industry legislation to discharge into the public sewers any matter that may interfere with the free flow of wastewater, which covers FOG from commercial kitchens.
Discharging into the public sewers any matter that may interfere with the free flow of the wastewater - and FOG falls squarely within this, congealing in the sewers and obstructing the flow. A kitchen that lets its FOG enter the sewer and cause that build-up is committing a criminal offence under the water industry legislation.
A kitchen that fails to control its FOG can face prosecution, with significant fines possible, and can be required to pay the costs of dealing with blockages, cleaning sewers, and remedying any flooding or pollution its FOG caused. So the consequences are both the legal penalty and the recovery of clean-up costs - substantial either way.
Chiefly the water companies - the sewerage undertakers that own and run the sewers - who enforce the rule against discharging blocking matter, can prosecute, and recover costs. The Environment Agency's role is the wider environmental protection, covering discharges to watercourses and controlled waters and the handling of waste, rather than the sewer itself.
Stop its FOG entering the public sewer by controlling it at source - typically by fitting a compliant grease trap or effective grease-management system that captures the fats, oils and grease from the wastewater before it reaches the drains. The system must be properly sized, maintained and emptied so it genuinely keeps the FOG out of the sewer.
Good practice in the kitchen alongside the grease trap - scraping and wiping grease from pans and plates before washing, and not pouring fat down the drain - reduces the FOG load and supports the grease-management system. The captured FOG and waste oils then need proper disposal as waste, connecting to the wider waste rules.
Grease is a problem both in your ductwork, as a fire risk, and in your drains, as a sewer-blocking offence - controlling it at every point, from the extract to the grease trap, is part of running a compliant kitchen.
