What to do if your bathtub is draining slowly

Common causes of a slow-draining bath

If your bath is draining slowly, there’s usually a clear reason behind it. Let’s take a look at the most common culprits.

Clogs in the pipes

Blockages in the pipes are the number one reason baths stop draining properly. Over time, things like:

• Hair
• Soap scum
• Dead skin cells
• Bath bomb residue
• Small foreign objects that have fallen down the plug hole (like jewellery or small toys)

…can all build up in the pipes, restricting water flow and causing backups.

Hard water deposit

If you live in a hard water area, minerals like calcium and magnesium can collect inside your pipes. These mineral deposits narrow the inside of the pipe over time, reducing drainage efficiency and increasing the chances of a full-on blockage.

Tree root intrusion

Houses with older pipes are more prone to cracks and joint damage, which makes them vulnerable to tree root intrusion. Roots can grow into these tiny gaps in search of moisture, then expand and trap debris, causing slow drainage or full blockages that usually require a professional to fix.

Pipes

As pipes get older (especially metal ones), they can start to corrode on the inside. This corrosion creates a rough surface where debris and sediment can build up, a bit like limescale in a kettle. Over time, that build-up can partially block the flow of water and slow things down.

Vents

Plumbing systems include vent pipes that allow air to flow and help drains function properly. If these vents become blocked (by leaves, animal nests, or other debris), it can cause negative pressure in your pipes, which results in slow drainage and gurgling sounds.

How to fix a slow-draining bath in 6 different ways

The good news is that many slow-draining baths can be fixed with a few DIY methods. Different clogs may respond better to different techniques, so you might need to try a few before finding what resolves the issue.

1. Remove any visible debris

Start by inspecting the plughole. If you can see hair or gunk just below the surface, put on some gloves and try to pull it out using your fingers or a bent wire coat hanger. Be gentle, as you don’t want to damage the pipe or push the blockage further down.

2. Boiling water

This is a simple, eco-friendly method that can help to dissolve soap scum, grease, and minor build-ups. Boil a full kettle of water and let it cool slightly before slowly pouring it down the drain in stages.

Make sure to be careful if your plumbing uses plastic pipes, as pouring freshly boiled water directly into them can cause damage. If you're unsure what kind of pipes you have, it’s best to use warm (not boiling) water instead.

3. Use a plunger

Place the plunger over the drain and make sure it’s sealed tightly. Fill the bath with enough water to cover the rubber part of the plunger, then push and pull firmly several times. The pressure can help dislodge stubborn clogs sitting deeper in the pipes.

4. Baking soda and vinegar

Pour about half a cup of baking soda down the drain, followed by a cup of white vinegar. Cover the plughole with a cloth or plug and leave it to fizz for 15–30 minutes, then follow with boiling (or warm) water. This natural chemical reaction can help break down grease and grime.

5. Drain snakes

A drain snake (sometimes also called a plumber’s auger) is a long, flexible tool that can reach deeper into pipes to pull out or break up clogs. Insert the snake into the drain, turn the handle to grab or loosen the blockage, then pull it out carefully.

6. Chemical cleaners

As a last resort, you can try a commercial drain cleaner, but be cautious here. These products contain strong chemicals that can be harmful if misused or used too frequently, and they may damage older pipework. Make sure to always follow the manufacturer’s instructions and wear protective gloves when handling chemical cleaners.

How to prevent a slow-draining bath

Prevention is always better than a cure. With a few simple habits, you can help keep your bath draining freely and avoid repeat blockages.

Use drain catchers

Drain catchers (also known as hair catchers) sit over or inside the plughole to catch hair, soap bits, and debris before they go down the drain. Just remember to empty and rinse them regularly.

Regular cleaning

Clean your bath drain once a week by removing surface debris and flushing it with hot water. A monthly treatment with baking soda and vinegar can also help keep things flowing smoothly.

Flush the bath with hot water

After using products like bath oils or thick soaps, run hot water down the drain for a minute or two. This helps melt away any lingering residue and prevents it from sticking to the inside of your pipes.

Avoid pouring oily products down the bath drain

Body oils, heavy conditioners, bath bombs, and other thick or greasy toiletries can solidify in your pipes and contribute to clogs. Try to use them sparingly, and always follow up with a hot water flush if you do.

When do I need to call a plumber for a slow-draining bath?

If you’ve tried all of the above methods and your bath is still draining slowly, it’s time to get a professional plumber in to help. Plumbers have the tools and expertise to diagnose more serious issues like tree root intrusions, collapsed pipes, or persistent blockages that you can’t reach yourself.

They’ll be able to inspect the system, remove the blockage safely, and ensure everything is running smoothly again.

Peace of mind starts with our Plumbing and Drainage cover

At HomeServe, we know that plumbing problems don’t wait for a convenient time. That’s why our Plumbing and Drainage cover is designed to give you peace of mind, knowing that help is just a phone call away when you need it most.

Whether it’s a slow-draining bath or something more serious, our friendly, professional engineers are ready to fix it quickly and efficiently so you can get back to relaxing.