Television DIY expert Nick Knowles has issued a stark warning to UK households, urging them to change their habits to prevent serious plumbing disasters and potential flooding in their homes.
The Common Kitchen Mistakes That Cause Chaos
Appearing on BBC Morning Live on 16 January 2026, the presenter of DIY SOS and other popular shows highlighted a frequent error made in kitchens and bathrooms across the country. Knowles stressed that many people inadvertently create "a massive problem" by disposing of certain items down sinks and toilets, unaware of the damage they cause.
"Whether you're dealing with the kitchen sink, the shower or the toilet, it's crucial to know this," he advised the audience. Taking simple preventative steps now, he argued, can stop an emergency situation from developing later.
The Worst Offenders for Your Drains
Knowles was unequivocal about the primary culprits. "Oil and fat in particular is a really, really bad thing. Do not put oil and fat down your drains," he stated firmly. Instead of pouring it away, he recommended letting it cool, storing it in a container, and disposing of it responsibly, even suggesting a trip to the local dump.
He also cautioned coffee lovers, explaining that seemingly harmless coffee grounds are a major contributor to blockages. "They're heavy, they tend to sit in the u-bend then combine with other things like oil to create a blockage." As a beneficial alternative, Knowles pointed out that coffee grounds are excellent for gardens, releasing nitrogen that is "really good for growing things." He referenced experts from the College of Agriculture and Life Sciences, who recommend composting grounds, making compost tea, or spreading them directly on soil, though he noted they should be kept away from tomatoes and lavender.
Another surprising item on the banned list is flour. "I don't know if you remember when you were kids, you made glue out of flour. Well, it does the same thing in your drain," he explained, joking that its binding power was so strong the Romans used it in cement—a quip that drew laughter from the studio. "No, I completely made that up," he confessed.
Wet Wipes and the Simple Rule to Remember
Moving to the bathroom, Knowles warned against flushing "wet wipes and things like dissolvable wipes," even those marketed as environmentally friendly. These should be placed in a bin, he said, similar to the disposal method for female sanitary products.
His advice aligns with a public campaign from Thames Water, which urges people to simply "bin it." The water company warns that flushing inappropriate items can clog pipes, block sewers, and cause internal flooding. They promote the easy-to-remember 3 Ps rule: only Pee, Poo, and (toilet) Paper should go down the toilet.
Thames Water's guidance expands the list of bin-bound items to include nappies, cotton wool, dental floss, condoms, and hair. For the kitchen, they advise binning food leftovers, noting that hot water and washing-up liquid won't prevent scraps from building up in pipes. They also recommend taking chemicals, solvents, engine oil, paint, and medicines to appropriate disposal points.
Nick Knowles concluded with straightforward advice: "If you keep those in mind, you probably won't have a problem in the beginning." By being mindful of what goes down drains and toilets, homeowners can avoid costly, messy emergencies and protect their local sewer systems.
