How to unclog a drain

Updated 2026-09-04 · 9 min read

Isometric cutaway of a sink drain with the P-trap removed and an auger beside — Sink drain cutaway with the P-trap removed and a hand auger coiled beside it.

Escalate in order, stop when it flows

Drain clearing is an escalation, and the order exists because each step costs more and risks more than the one before it. Start at the cheapest reversible move and stop the moment you have flow. Skipping to the middle is how a stopper linkage ends up snapped.

Escalation order for a single slow fixture
Step	Tool	Clears
1	Remove and clean the stopper	Hair and soap at the top of the tailpiece
2	Plunger, with the overflow blocked	Soft blockages within a few feet
3	Hand auger through the drain	Hair and debris in the trap and arm
4	Pull and clean the P-trap	Anything sitting in the trap, including jewellery
5	Auger the trap arm to the branch	Blockages past the trap
6	Cable the branch or main	Roots, grease, paper — call it in

Do not reach for chemical drain cleaner

Caustic cleaners rarely clear a real blockage and they turn the next step dangerous: whoever opens that trap gets a face full of lye. If one has already been poured, say so before anyone starts work.

By fixture

Lavatory. Almost always hair on the pop-up stopper. Loosen the pivot nut behind the tailpiece, pull the stopper, clean it. Ten minutes, no tools past a pair of pliers.

Tub. The overflow plate hides a linkage that collects everything. Unscrew the plate, lift the assembly out, clean it. Block the overflow before you plunge a tub or you are just moving air.

Kitchen sink. Grease and food, usually in the trap or just past it. If there is a disposal, run it first — the blockage may be in the unit rather than the pipe. On a double bowl, block the other bowl before plunging.

Shower. Hair at the strainer or in the trap. A plastic barbed hair tool through the strainer clears most of them without opening anything.

Isometric detail illustration for the how to unclog a drain guide — Sink drain cutaway with the P-trap removed and an auger coiled beside it.

When to stop and call

Three signals mean the problem is not at that fixture. More than one fixture is slow at once. A drain gurgles when a different fixture is used. Or water comes up somewhere it should not — a shower filling when the toilet flushes is the classic main-line signature.

All three point past the branch, and a hand auger will not reach. That is a cable or a jetter job — see what each one costs and buys on the drain cleaning cost page.

A gurgle may be venting, not blockage

Gurgling can also mean a blocked or missing vent, which is a different fault with a different fix. The vent requirements guide covers how to tell.

If it keeps coming back

The same drain blocking every few months is a symptom of the pipe, not of what went down it. The three usual causes are a belly holding water, an offset joint catching debris, and root intrusion at a joint. A camera settles it in twenty minutes.

Grade is the one that is not fixable from inside. If the camera shows standing water in a level section, the run was laid without enough fall — check the required minimum with the slope calculator and price the correction rather than the next cleaning.

Keeping it clear

Strainers on every fixture, grease into the bin rather than the sink, and hot water run after washing up do more than any additive sold for the purpose. In a house with long hair in it, cleaning the tub linkage twice a year prevents most of the calls.

"Flushable" wipes are not. They are the single commonest cause of a main-line blockage in a house with no roots and no bellies.