In short, drains are built to carry water, human waste and toilet paper. Almost everything else can cause trouble. A small item that seems harmless can snag in a pipe and collect other waste until the flow stops.
This guide covers the usual culprits, including wipes and cooking fat. It uses advice published by Yorkshire Water and the UK government. It also explains what to do instead, and when to call for help.
Wipes do not belong in the toilet
Yorkshire Water says wipes and sanitary products should never be flushed down the toilet, even the biodegradable ones. The company says they contain plastic fibres that can build up in pipes and cause flooding. It also says wipes cause nearly half of the blockages in Yorkshire.
In a 2022 news release, Yorkshire Water reported figures for 2021. Wipes were linked to 11,996 of the 26,790 blockages it cleared in that year. That is about 45 per cent. The company adds that many wipes do not break down in sewers like toilet paper does.
As a result, the safe habit is simple. Put used wipes in the bin, every time. A small lidded bin in the bathroom makes this easy. Next, tell everyone in the house, including guests, where it is. Visitors often flush wipes simply because there is no obvious bin.
What about wipes labelled flushable?
Labels cause confusion here. In May 2023, the government's environment department wrote to wipe makers asking them to rethink the word "flushable" on packs. It said labels such as "fine to flush" may lead people to flush wipes rather than bin them.
Yorkshire Water gives clear advice here: never flush wipes, even ones sold as biodegradable. If you are unsure about any item, the bin is always the safe choice.
Fat, oil and grease
First, a point about kitchens. Many people pour cooking fat away while it is still hot and liquid. It looks harmless at that stage. However, the problem starts a little further along the pipe.
Fats, oils and grease are a different problem. Yorkshire Water explains that they turn solid in your pipes. Washing them away with hot water or washing-up liquid does not stop this. Over time, these fats can form large blockages called fatbergs.
For most homes, the kitchen sink is the usual starting point. Even a small amount of grease from a roasting tin adds up when many homes do the same. A blockage like this may affect your own drain first, then a shared drain.
However, Yorkshire Water also notes that when fat causes a blockage, it writes to everyone who shares the drain. That means one household's habits can affect the whole street.
Why small blockages grow
A blockage rarely starts as a big one. First, one wipe or lump of fat catches on a rough joint or a bend. Then hair, paper and more waste stick to it. In time, the pipe narrows until water can no longer pass.
Yorkshire Water says blockages like this can restrict toilet use at homes. They can also cause sewage to escape into properties, gardens or roads. For this reason, stopping the habit is far cheaper than clearing the result.
What to do instead
In practice, a few easy habits make a real difference. Yorkshire Water suggests these steps in the kitchen:
- Wipe leftovers off plates with kitchen roll before washing up.
- Use a sink strainer to catch food waste.
- Let cooking oil cool, pour it into a container and put it in the bin.
- Let fat cool until it sets, then scrape it into the bin.
Likewise, in the bathroom, bin wipes, tampons, pads, wrappers and applicators. Wrap sanitary products before you throw them away. Yorkshire Water also names the "3Ps" rule: only pee, poo and toilet paper go down the toilet.
Other items to keep out of the drain
In addition, the same advice applies to nappies, cotton buds and dental floss. Yorkshire Water lists these among items it does not want in its pipes. Construction debris and tree roots also appear on its list of regular causes of blockages, though roots are a drain problem rather than a habit.
When a blockage happens anyway, act quickly. A blocked toilet is often cleared with the right equipment, while a wider problem may need internal drain unblocking service. For other jobs, see our overview of drain unblocking.
Next steps
If a drain is slow or blocked, do not keep flushing. Stop using the affected toilet or sink, and check whether neighbours have the same problem. Local customers can read about blocked drains in Hull, and we also cover drain unblocking in Hornsea. Request a quote online and describe what is happening.