The short answer

Your drain needs cleaning when water drains slowly, smells appear or pipes gurgle. Water backing up is the clearest sign of all. Act at the first warning, because a small problem is cheaper to fix than a full blockage.

Every home drain gets dirty with use. Food, hair, soap and grease all go down the pipes, so some build-up is normal. You are not to blame, but you should check for the signs below.

Slow drainage

Slow drainage is the easiest sign to spot. Water lingers in the sink, bath or shower before it goes. Hair, soap and grease usually cause it, because they cling to the pipe wall and narrow it.

One slow sink is a minor matter. However, several slow fixtures at once point to a deeper problem. In that case, how to clear a main sewer line explains what may be going on.

Foul smells

A sewage smell is a clear warning. It can come from food waste rotting in a pipe, or from a blockage that traps gas. Therefore do not ignore a smell that comes back after you clean the sink.

Smells also attract pests over time. Our guide to common causes of blocked drains shows how waste collects in the first place.

Gurgling sounds

Gurgling means air is moving through water in a pipe. It often happens when a partial blockage slows the flow. For example, a bath may gurgle when you flush the toilet.

Some noise is normal, but a repeat noise needs a closer look. If you have a basement, read about a sewer backup in a basement to see how a gurgle can lead to a worse problem.

Water backing up

Water backing up is the sign you must not leave. Standing water in a sink, or a toilet that bubbles, shows the drain cannot cope. Sewage can also rise through the lowest fixture, so a bath is often the first to fill, as we explain in bathtub drain backing up.

If this happens, stop using the water. Keep it away from children and pets. Then send an enquiry, because repeated pressure can damage pipes.

Flies around drains

Small flies near a drain suggest waste is building up inside it. Drain flies breed in the film on the pipe wall. Because they are a health nuisance, clean the drain and look for the source.

What you can try yourself

Simple care can help small problems. Pour hot water down the sink after use, and use a strainer to catch food. A mix of bicarbonate of soda and hot water can also loosen light grease.

Do not go further than this if the drain keeps blocking. Methods to unblock clogged drains lists safe home steps. For a longer-term plan, see how can I keep my drain clear of blockage.

When to ask for help

Ask for help if the signs return after your own cleaning. The same applies when more than one fixture is affected. In these cases, a professional clean is usually the right step, because a plunger only moves the blockage. Jetting blocked drains is a common method, and how drain jetting can benefit you describes the results.

Outdoor problems need a different approach. If you can see water rising outside, read about a blocked drain outside the house. Not sure where to begin? Our guide on whether you need drain clearance will help.

How often to clean

Regular cleaning prevents most of these signs. The right gap depends on how many people use the drains. Our article on how often drains should be cleaned gives a practical guide. We also offer drain maintenance for owners who prefer a set routine.

Where we work

Our wider blocked drains help covers North London. For local pages, see drain unblocking in Cheshunt, drain unblocking in Potters Bar and drain unblocking in Southgate. Send the online enquiry form when you are ready.