Is your bathtub not draining as quickly as it should? Is the bathwater not draining at all? Let us help you to fix the problem. Read on to learn everything you need to know about unblocking a slow draining bathtub.

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There's nothing relaxing about stepping out of the bath and finding yourself standing in a puddle of lukewarm water.

A slow or blocked bathtub drain is one of the most common household plumbing problems - and in most cases, it's something you can fix yourself without specialist tools.

This guide walks you through the likely causes, the fixes worth trying at home, and the signs that it's time to call in a vetted plumber.

Why is my bathtub not draining?

In the vast majority of cases, a blocked bathtub comes down to one thing: something is clogging the drain or the pipes beneath it.

But it's worth understanding exactly what that something is, because the right fix depends on the cause.

Hair

Hair is the number one culprit. Over time, loose strands clump together in the drain trap and pipes, catching soap residue, dead skin cells, and other debris along the way.

The blockage grows gradually, which is why you might not notice a problem until drainage has become very slow or stopped altogether. Long-haired households are especially prone to this.

Soap scum

Soap residue coats the inside of pipes and slowly narrows the passage water needs to flow through. On its own it might not cause a full blockage - but combined with hair, it cements the problem.

Hard water and limescale

If your home is in a hard water area, minerals like calcium and magnesium can build up inside your pipework over time. This limescale narrows the internal diameter of the pipes and can cause persistent slow drainage even when there's no visible blockage.

Foreign objects

Small toys, bottle caps, hair clips, and wipes can all end up in the plughole - especially in family bathrooms. These can cause sudden, complete blockages rather than the gradual slowdown you get from hair and soap.

A faulty drain stopper

If the bath is draining slowly but there's no obvious blockage, the drain stopper could be the culprit. The stopper is connected to a lever mechanism behind the overflow plate (the round metal plate set into the bath wall, below the taps).

If the lever gets stuck in a closed or partially closed position, it prevents the drain from fully opening.

Old or corroded pipes

In older properties, pipework can corrode or narrow over time, making drainage sluggish regardless of what goes down the drain.

If your bath has always drained slowly since you moved in - and other drains in the house are also slow - this could be worth investigating with a drain specialist.

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How to fix a bathtub that won't drain

Start with the simplest fix and work your way down. You don't need any specialist tools for most of these methods - just patience and a pair of rubber gloves.

1. Remove visible hair from the plughole

Before reaching for any products, have a look down the plughole.

Put on rubber gloves and use your fingers or a bent wire coat hanger to pull out any hair or debris sitting in or just below the drain. This alone solves the problem more often than you'd think.

2. Try boiling water

For minor blockages caused by soap scum or grease, boiling water can be surprisingly effective. Boil a full kettle, let it cool for a minute or so, then pour it steadily down the drain in stages.

One important note: if your plumbing uses plastic pipes, use hot rather than freshly boiled water to avoid any risk of softening or warping the pipe.

3. Baking soda and vinegar

If boiling water alone doesn't clear it, a baking soda and vinegar solution can help break down stubborn soap and grease build-up.

n.b. This method only works once the standing water has drained away (even slowly) - it won't work if the bath is still full.

Steps:

1. Pour one cup of baking soda down the drain

2. Immediately follow with one cup of white vinegar

3. The two will react and fizz - this is normal and that's the point

4. Leave it for 15-30 minutes without adding anything else

5. Flush with hot (not boiling) water to rinse everything through

4. Use a plunger

A plunger is ideal when there's standing water in the bath. Make sure the plunger cup fully covers the plughole to create a proper seal, then push down and pull up firmly several times in a row.

Before you start, block the overflow opening with a damp cloth or your hand - this helps direct the suction force downward into the blockage rather than letting air escape through the overflow.

It may take several rounds of plunging to shift a stubborn clog.

5. Try a drain snake

If plunging hasn't worked, a drain snake (also called a plumber's auger or drain rod) can reach deeper into the pipe to physically break apart the blockage.

Feed the flexible cable into the plughole, push it down until you feel resistance, then twist and push to break up the debris.

Pull the snake back out slowly and rinse the drain with hot water once you're done.

6. Chemical drain cleaners

Shop-bought drain unblockers can dissolve hair and soap scum effectively - but use them as a last resort. The chemicals involved can irritate skin and eyes, and frequent use can damage older pipework.

Always follow the product instructions carefully, ventilate the bathroom, and keep children away.

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Bathtub draining slowly but not blocked - what's going on?

If you've checked for visible blockages and tried the fixes above without success, the problem might not be a blockage at all.

Faulty drain stopper

The stopper mechanism sits behind the overflow plate on the bath wall. Remove the overflow plate (usually two screws) to access the lever and stopper. Check that the lever moves freely and isn't jammed in a closed position. This is a fiddly job and one where calling a plumber is often the sensible call.

Corroded or narrowed pipes

Old pipework can slow drainage gradually over years without any single obvious blockage. A drain specialist can inspect the pipes with a CCTV drain camera to identify the issue - and can reline or clear the pipes as needed.

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When to call a plumber or drain specialist

DIY fixes work well for most straightforward blockages. But there are times when calling a professional is the right move:

• The bath still won't drain after trying all of the above

• Blockages keep coming back every few weeks

• Multiple drains in the house are slow at the same time

• There are gurgling sounds or bad smells coming from the drain

• You notice water backing up or pooling around the bath

• You suspect a problem with the drain stopper mechanism or old pipework

A checked and well-reviewed plumber can diagnose the issue and clear it quickly. For blockages further down the system, a drain clearance specialist may use high-pressure water jetting or CCTV equipment to find and fix the problem properly.

Not sure whether you need a plumber or someone with more specialist drainage expertise? Our guides can help you work out who to call and what to expect to pay.

How much does it cost to unblock a bath?

For cost guidance on drain unblocking and plumber call-out fees, take a look at our drain unblocking cost guide and our plumber cost guide.

Alternatively, why not try out our dedicated pricing tool? Based on real job data from our tradespeople.

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How to prevent your bathtub drain from blocking again

Clearing a blocked bath drain is satisfying - keeping it clear is even better. A few simple habits go a long way.

Use a hair catcher

A drain cover or hair trap sits over or inside the plughole and catches hair before it can get into the pipe. Empty and rinse it after every bath. They cost very little and save a lot of effort.

Flush the drain weekly

Once a week, pour hot water down the drain to wash away soap and product residue before it has a chance to build up.

Monthly baking soda and vinegar treatment

A quick baking soda and vinegar flush once a month - even when there's no blockage - helps keep pipes clear.

Be careful with bath products

Bath oils, thick conditioners, and bath bombs leave behind residue that coats your pipes. If you use them, follow up with a good hot water flush.

Don't pour grease or oil down the bath drain

It solidifies in the pipes.

Finding a plumber you can trust

On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.

Whether it's a stubborn bath blockage, a problem further down the drainage system, or a faulty stopper mechanism, a vetted plumber or drainage specialist can sort it quickly and properly.

Bathtub not draining - quick checklist

Before calling a plumber, have you tried...

• Pulling visible hair from the plughole

• Pouring hot water down the drain

• Baking soda and vinegar treatment

• Plunging with the overflow covered

• Snaking the drain with a drain rod

• Checking the overflow plate and stopper lever

Bathtub draining FAQs

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