One mistake many people make while cooking does not only cause serious damage, but is also crime.
Brits risk two years in jail for easily made cooking mistake (Image: Getty)
UK households are being urged to reconsider how they dispose of cooking oils, fats, and grease after legal experts and water companies highlighted a little-known law that carries surprisingly severe penalties. Under Section 111 of the Water Industry Act 1991, it is a criminal offence to discharge anything into a public sewer that could cause damage, blockages, or interfere with treatment.
Fats, oils, and grease, collectively known as FOG, fall squarely under this rule. Those found guilty on indictment face a maximum penalty of two years’ imprisonment, an unlimited fine, or both, with the possibility of additional daily fines if the offence continues after conviction. Scotland has a parallel law under the Sewerage (Scotland) Act 1968, which similarly targets material that interferes with the free flow of sewers.
Oil can’t be poured down the drain, but needs to be properly disposed of (Image: Getty)
While prosecutions have historically focused on businesses and repeat offenders, the law applies to individuals as well. Households are often left footing costly bills when blockages occur on private drains within their property boundaries.
Despite the risks, surveys suggest the problem is widespread.
A 2023 study found that 27 percent of UK adults admitted pouring fats down the kitchen sink, 22 percent disposed of them in outside drains, and 11 percent flushed them down the toilet.
Older polling paints an even starker picture, with a 2019 survey revealing that nearly half of UK adults had poured oil or fat down the sink at some point.
Seasonal spikes, such as during Christmas, are particularly common, as leftover cooking fats are often discarded without a second thought.
Prosecutions for sewer blockages caused by fats and oils, while still relatively rare for households, are increasingly common among businesses.
In 2021, a Henley-on-Thames pub was fined over £16,000 after its landlord admitted allowing cooking fats to enter the sewer system.
More recently, the China Panda takeaway in Fulham was ordered to pay over £13,000 following repeated breaches.
Cafe Saffron in Codsall was convicted in 2016 and fined nearly £5,500 for similar offences. In 2024, Thames Water reported that courts had imposed over £265,000 in fines and costs for severe sewer abuse offences committed by multiple food businesses.
These cases underscore the scale of the problem, with Thames Water alone spending millions annually tackling approximately 75,000 blockages, many of which are caused by fats and wipes combining into the notorious “fatbergs.”
Households are advised to let cooking fats and oils cool, then scrape or pour them into a container to be binned or taken to a recycling point.
Water companies stress that hot water and washing-up liquid do not prevent blockages, as fats re-solidify downstream.
Businesses are urged to fit and maintain grease traps or separators, use licensed waste carriers, and keep disposal records to demonstrate compliance with their duty of care obligations.
