Pouring leftover cooking oil down the sink is a common mistake that can lead to blocked drains, fatbergs, and serious plumbing issues. Waste experts have now shared the correct disposal method, and they all gave the same answer: let the oil cool and solidify, then put it in the general waste bin.
Speaking to Express.co.uk, Martin Garbutt, head of technical governance at Ding, explained why oil should never go down the drain. "Fats and oils are among the most common contributors to household drain blockages," he said. "Although they enter the drain as liquids, as happens with most sauces, they solidify as they cool. This causes them to stick to the inside of the pipes, narrowing the passage of water and creating blockages."
How to get rid of cooking oil
Garbutt advised leaving fats and oils to cool and solidify before placing them in household waste. For most households, the proper method is to let the oil cool completely, decant it into a sealed container such as the original bottle or a jar, and put it in the general waste bin. Many local councils and household waste recycling centres also accept used cooking oil for recycling into biodiesel.
Chris Houghton, home expert at HomeServe, echoed this advice: "Disposing of oil properly is easy. Let it cool completely in the pan, then pour it into a sealable container such as an old jar or bottle, screw the lid on and put it in your general waste bin."
For small amounts, Houghton suggested wiping the pan with kitchen roll and binning it. For larger quantities, such as after using a deep fat fryer, most household waste recycling centres will take used cooking oil, so checking the local council's website is recommended. Some councils also accept small amounts soaked into kitchen roll in food waste caddies.
How cooking oil damages plumbing and public sewage
Houghton also highlighted that improper oil disposal affects more than just your own property. "Hot oil looks harmless because it's liquid, but as soon as it cools in your pipes, it thickens and sets, coating the inside of the pipework. Food scraps and other debris then stick to it, and over time, it builds into a blockage."
He added: "Even modest quantities solidify as they cool, combining with other waste matter in pipes to create fatbergs — one of the most expensive and destructive issues currently plaguing the UK's sewer network. Once it's past your property, the same fat combines with wet wipes and other waste in the sewers to form fatbergs, which can cause sewage to back up into homes and streets."
A single blocked drain can cost thousands of pounds to clear, and the environmental consequences of oil entering waterways are considerable.
Jamie Campbell, Operations Director at Kane Enviro, agreed with both experts: "Used cooking oil should never go down the sink. For larger quantities, specialist cooking oil collection services will collect and process it commercially. The key message is simple: keep it out of the drain at all costs."
