How to unblock a drain

Most single-fixture blockages — a slow sink, a bath that will not drain, a toilet that backs up but eventually clears — are caused by something caught close to the fixture rather than deep in the drain run, and respond to a few simple steps before anything more involved is needed.

What to try first

A sink or bath plunger, used with enough water in the basin to cover the plunger cup and a firm, steady push-pull motion rather than one hard slam, clears a large proportion of kitchen and bathroom blockages. For a sink specifically, clearing and cleaning the U-bend underneath (a bucket underneath first) often finds the culprit directly — usually food debris or a build-up of grease. For a slow-draining bath, a wire drain snake fed a short way down often pulls out the hair causing it.

What to avoid

Caustic drain cleaners bought from a supermarket can actually make the job harder and more dangerous for whoever attends afterwards — the chemical residue reacts unpredictably with equipment and can cause burns. If a plunger and a manual approach have not worked, it is worth stopping there rather than escalating with stronger chemicals.

When it is more than one fixture

If more than one thing is draining slowly at once — a sink and a nearby bath, for instance — the blockage is likely further down the shared run rather than at either individual fixture, and needs proper drain rods or jetting rather than a plunger. This is where our drain unblocking service takes over, with the right equipment for a blockage that is genuinely further down the line.

When it keeps coming back

A drain that clears fine each time but blocks again every few months in the same spot is not really presenting as a blockage problem — something is physically wrong with the pipe at that point, most often root ingress or a partial collapse, catching debris every time. A CCTV drain survey finds the actual cause rather than clearing the same symptom on repeat, and if it turns out to be structural, drain repairs covers fixing it properly, often without digging anything up.

Outside drains and gullies

An overflowing gully or an outside drain is worth checking for leaves and debris caught over the grate before assuming it is blocked further down — a surprisingly common and easy fix in autumn.