You should avoid putting fat, oil and grease, food scraps, coffee grounds and other solid waste down a kitchen sink. These can build up inside the waste pipe and drain, and are a common cause of blocked sinks, although not the only one.
Small changes in habit can help keep the sink draining well. They also help reduce the build-up that can cause smells and slow drainage over time.
Fat, Oil and Grease
Cooking fat, oil and grease may be liquid when hot, but they cool and stick to the inside of pipes. Over time this layer can trap food and other waste, narrowing the pipe. Water companies run campaigns asking people to keep fats out of sinks for this reason.
Letting fat cool and putting it in the bin, and wiping greasy pans with kitchen roll before washing them, can help. Washing-up liquid and hot water may move grease further along the pipe, but they do not stop it settling again as it cools.
Food and Other Solids
Food scraps, rice, pasta and peelings can collect in the trap and waste pipe. Coffee grounds and tea leaves can settle and clump together. Eggshells, bones and seeds do not break down easily either.
Scraping plates into the bin or a food waste caddy before washing up, and using a sink strainer, can stop much of this reaching the pipe. Emptying the strainer into the bin, rather than tapping it out into the sink, keeps the waste out of the pipe.
Things That Do Not Belong in a Sink
Some items should never go down a sink. These include paint, solvents, grout or filler, and medicines. As well as causing blockages, some of these can harm the wider environment. Your local council can advise on how to dispose of them safely.
Avoid relying on strong drain chemicals to keep the sink clear. They are not a substitute for keeping waste out in the first place. Using them often can be harmful, and mixing different products can give off dangerous fumes.
If the Sink Is Already Slow
If you have a waste disposal unit fitted, follow the maker’s guidance on what it can handle, as some foods can still cause problems further along the pipe.
Even with good habits, sinks can still slow down over time. A gradual build-up, a shared waste with an appliance or a problem further along the drain can all cause problems.
If your sink is draining slowly or keeps blocking, our page on clearing a blocked sink explains how kitchen and bathroom sink blockages are assessed and cleared. If the problem is with the taps, waste fittings or sink itself rather than a blockage, our sink repair page may be more relevant.
If your kitchen sink is draining slowly or keeps blocking in your Poole home, a plumber can look at the cause and explain the options.