Sort out slow drains through the house

A weekend project to clear slow drains throughout the house, working from basin to outside gully, calling a plumber if blockages persist.

Guides in this project

01Unblock a bathroom basin 02Unblock a shower drain 03Unblock a bath 04Unblock a kitchen sink 05Unblock an outside drain 06Fit a hair catcher or drain guard

AB-01Plan the whole-house drain checkBefore you start, run water in every basin, shower, bath and sink and watch how fast it drains, so you know which ones actually need work. This is usually a one-day job if only one or two fixtures are slow, or a full weekend if the whole house drains badly and you end up at the outside gully. Buy your kit upfront: a set of drain rods, a sink plunger, rubber gloves, dust sheets and a bucket. You don't need to turn the water off to open a sink or basin trap, but put a bucket underneath and make sure nobody runs a tap while it's apart.

1 each · Drain rod set

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1 each · Sink plunger

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1 pair · Rubber gloves

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1 each · Bucket

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2 each · Dust sheets

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AB-02Clear the bathroom basinFollow the Unblock a bathroom basin guide for this fixture. Basins are usually blocked by hair and soap scum sitting in the trap, so this is normally quick. Do this one first, as it's the easiest and gives you confidence before tackling the others.

1 bottle · Drain unblocking gel

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AB-03Clear the shower drainFollow the Unblock a shower drain guide. Shower drains clog with hair and skincare residue, often right at the grille or just below it. If the shower is on an upper floor, check the ceiling below over the next day or two for damp patches, in case the trap seal was disturbed.

1 each · Wire drain hook tool

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AB-04Clear the bathFollow the Unblock a bath guide. Check the overflow as well as the main plughole, since a blocked overflow can make the bath drain slowly even after you've cleared the trap. Baths often share pipework with a nearby basin, so a bath that's still slow after this step may point to a blockage further down the run.

1 each · Overflow cleaning brush

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AB-05Clear the kitchen sinkFollow the Unblock a kitchen sink guide. Grease and food debris are the usual cause here, so expect a messier job than the bathroom fixtures. If your kitchen has an electric waste disposal unit and it needs replacing or rewiring rather than just unblocking, that's a job for a registered electrician, not something to DIY.

RULES

1 bottle · Caustic-free drain unblocker

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KNOW THE RULES

Replacing or wiring a waste disposal unit is a job for a registered electrician. It isn't notifiable in England, but in Wales kitchen electrical work can be notifiable, so check if unsure.

AB-06Clear the outside drainFollow the Unblock an outside drain guide. Lift the manhole cover carefully and check for tree roots or silt build-up, which are common causes of a recurring outdoor blockage. If you need to cut back a tree or hedge to get at the drain run, check first for nesting birds (roughly March to August) and for a Tree Preservation Order or conservation area status. If the blockage sits beyond your boundary in the shared or public sewer, contact your water company rather than digging it up yourself.

RULES

1 each · Manhole cover key

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2 each · Extra drain rods

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KNOW THE RULES

Check for nesting birds before cutting any tree or hedge, and check for a Tree Preservation Order or conservation area status first. Blockages in the shared public sewer are the water company's responsibility, not a DIY job.

AB-07Flush the system and decide if you need a professionalRun water through every fixture in order, from the basin down to the outside gully, and check each one drains at a normal speed. If one or more fixtures are still slow, or you notice a bad smell, gurgling, or the same blockage keeps coming back within weeks, the problem is likely further down the pipework than DIY rodding can reach. At that point, call a drainage specialist for a CCTV drain survey, which typically costs £100 to £250 and will show exactly where the blockage or damage is.

1 bottle · Drain cleaning fluid (maintenance dose)

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