Nick Knowles, presenter of BBC DIY SOS, appeared on Morning Live on June 26 to warn viewers about the dangers of pouring liquid from tinned tuna down kitchen sinks. While the action may seem harmless, it can contribute to the formation of fatbergs—large solid blockages in sewer systems composed of fats, oils, greases, and other debris.
What Are Fatbergs and Why Are They Dangerous?
Fatbergs can cause severe flooding in homes, lead to raw sewage spilling into waterways, harbour antibiotic-resistant superbugs, and cost millions of pounds in manual, high-pressure extraction work. According to Knowles, even small amounts of oil from tinned tuna can accumulate with other substances to create blockages.
"Don't pour your oils down the sink. I mean, most people know not to pour oils down your sink in the bathroom or in your kitchen now. But actually, most of us will drain a tin of tuna into the sink. With the oil that's in a tin of tuna, or maybe the fat from an air fryer, or coffee grounds, all these things add to create a block," Knowles said.
How to Dispose of Tinned Tuna Liquid Properly
To prevent blocked pipes and fatbergs, Knowles advises against pouring tuna brine or oil down the sink. While brine is mostly water and salt, leftover fish oils and bits can mix with soap and cause serious plumbing issues. Instead, absorb small quantities of liquid with kitchen roll and dispose of it in the bin, decant it into a sealed container, or reuse it for cooking.
After cooking with oil, Knowles recommends letting it cool completely before scraping it into a disposable container, such as a baked bean tin, and throwing it in the bin.
Other Items to Avoid Pouring Down Drains
Knowles also warned against pouring food grease, food scraps, and coffee grounds down drains. Additionally, he cautioned against flushing cotton buds, nappies, or wet wipes down the toilet. "Wet wipes in particular... All the governments, England, Ireland, Scotland, Wales, and Northern Ireland, are going to be stopping the use of plastics in wet wipes, which will actually be a major boon in terms of stopping that happening," he said.
Warning Signs of a Blockage
Knowles outlined several signs indicating a likely blockage in drains or the sewer network: slow draining, odours, gurgling noises, and pooling water by manholes. If you suspect a blockage near your property, contact your water provider first.
Scale of Fatbergs
To illustrate the size of fatbergs, Knowles shared startling comparisons: "In cities, you can go on tours and walk through the drains. A fatberg found near Terminal Five at Heathrow was the size of seven hundred suitcases, or the equivalent of five football pitches."
