How do I unblock a shower drain?

How to clear a slow shower drain, which is almost always hair, and how to stop it happening again.

Difficulty: beginner
Time: 30 min
Read: 2 min
Safety: caution

Short answer

Take the drain cover off and pull the hair out with a flexible plastic drain tool or a bent wire hook — it's hair and soap in essentially every case. Then flush with hot water. Fit a hair catcher afterwards and you'll rarely have to do it again.

Shower drains block with a mat of hair bound together by soap scum, sitting just below the grate. It's unpleasant and it's simple: a flexible barbed drain tool costs very little and pulls the whole mat out in one go, which is faster and far more effective than any chemical.

Safety

Wear gloves. Don't pour caustic drain cleaner in first — if you then have to work by hand you'd be reaching into a corrosive liquid. If you have already used a chemical cleaner, flush the drain thoroughly with water and wear eye protection.

What you'll need

Flexible barbed drain tool or a bent wire
Rubber gloves
Screwdriver for the cover
Bin bag
Old toothbrush (optional)

Step by step

Remove the drain cover — usually a lift-out grate or one or two screws.Some shower trays have a bayonet fitting that twists off.
Put gloves on and pull out anything visible.Expect a substantial hair mat. Have a bin bag ready.
Feed a flexible barbed drain tool down and pull it back up slowly.The barbs catch the hair. Repeat several times — there's usually more than the first pull suggests.
Clean the grate and the trap surround with a brush.Soap scum on the grate itself contributes to catching the next lot of hair.
Flush with a kettle of hot — not boiling — water and a squirt of washing-up liquid.It clears the residual soap film. Boiling water can damage plastic shower traps.
If it's still slow, remove and clean the trap if it's accessible.Some shower trays have a removable trap accessible from the drain itself; others need access from below.
Fit a hair catcher over the drain.This is the actual solution. It costs a couple of pounds and prevents nearly all repeat blockages.

Tips

Do it every few months as maintenance rather than waiting for a blockage. It takes two minutes when it isn't blocked.
Bicarbonate of soda followed by vinegar helps break down soap scum as maintenance, but won't shift an established hair mat.
If several fixtures are slow at once, the problem is further down the system rather than in the shower.
A blocked shower that also smells usually means the trap has dried out or is full of decomposing material — clean it rather than masking it.

Common mistakes

Reaching for chemical drain cleaner first — It's caustic, often doesn't shift a hair mat, and makes subsequent manual work hazardous.
Pouring boiling water into a plastic trap — It can soften and distort the fitting. Hot from the tap is the safe limit.
Clearing it and not fitting a hair catcher — You'll be doing it again in three months.

Questions people ask

What's the best tool for a hair blockage?

A flexible plastic barbed drain tool. They cost very little, reach further than fingers and pull the mat out whole. Far more effective than chemicals for this specific blockage.

Why does my shower drain smell?

Either decomposing hair and soap in the trap, or a dried-out trap letting drain gases up. Clean it, and if it's rarely used, run water through weekly to keep the trap sealed.