Installing a bath waste is a relatively straightforward plumbing job, but getting the seals and connections right is essential. A poorly installed waste fitting can allow water to leak underneath the bath, where the problem may go unnoticed until it causes damage.
To install a bath waste, fit the waste body through the bath's waste hole with the supplied seals, secure it from underneath, connect the overflow where applicable and then attach the waste to the trap and drainage pipe. Always test every connection for leaks before fitting the bath panel or finishing the installation.
Below, we'll take you through the process step by step.
What Is a Bath Waste?
A bath waste is the fitting installed in the drainage hole at the bottom of your bath. It allows water to leave the bath while also providing a way of closing the outlet when you want to fill it.
Depending on the design, the waste may use a:
- Plug and chain
- Click-clack mechanism
- Pop-up mechanism
- Combined bath filler and waste
Most baths also have an overflow, which provides an additional drainage route if the water rises too high.
If you're buying a new bath, check whether a waste is supplied or needs to be purchased separately. Asturias Bathrooms offers a range of bath wastes in different mechanisms and finishes.
What You'll Need
The exact tools depend on the waste and bath, but you'll typically need:
- Bath waste and overflow
- Bath trap
- Adjustable spanner or suitable grips
- Screwdriver
- Cleaning cloth
- Bucket or container
- Plumber's silicone was specified
- Appropriate waste pipe and fittings
Always read the instructions supplied with your particular bath waste before installation.
How to Install a Bath Waste
Step 1: Check the Bath and Waste
Before fitting anything, make sure the waste is compatible with your bath.
Check the waste opening, overflow position and supplied components.
If you're installing a completely new bath and haven't settled on its dimensions yet, our How to Choose the Right Bath Size guide covers the measurements worth considering before installation.
Step 2: Clean Around the Waste Hole
Make sure the area around the bath's waste opening is clean and dry.
Remove any dust, packaging or debris that could prevent the seal from sitting flat against the bath.
Step 3: Fit the Waste Body
Position the supplied seal or washer according to the manufacturer's instructions.
Insert the upper section of the waste through the waste hole from inside the bath.
From underneath, fit the corresponding washer and waste body or retaining section.
Hold the upper section in position while tightening the connection below.
The fitting needs to be secure enough to create a watertight seal, but don't overtighten it. Excessive force can damage washers, fittings or potentially the bath itself.
Step 4: Connect the Overflow
Most standard bath wastes incorporate an overflow.
Position the overflow fitting against the overflow opening near the top of the bath and install its seal as instructed by the manufacturer.
Secure the overflow cover from inside the bath, then connect the overflow pipe to the main waste assembly.
Make sure the pipe isn't twisted, kinked or placed under unnecessary tension.
Step 5: Connect the Bath Trap
Connect the bottom of the bath waste to a suitable bath trap.
The trap retains a small amount of water after the bath drains, helping prevent unpleasant smells from the drainage system from entering the bathroom.
Check that all compression washers and seals are positioned correctly before tightening the connections.
Step 6: Connect to the Waste Pipe
Connect the trap to the bathroom's waste pipe.
The exact arrangement will depend on your existing plumbing and the position of the bath.
Avoid forcing components into alignment. Poorly aligned waste connections can place strain on fittings and increase the likelihood of leaks.
If significant pipework alterations are required and you're not confident carrying them out, use a qualified plumber.
How Do You Seal a Bath Waste?
The watertight seal around a bath waste normally comes from the washers and seals supplied with the fitting.
Some manufacturers may also specify the use of sanitary silicone or another sealant.
Follow the instructions for your particular waste rather than automatically adding sealant everywhere. Incorrectly positioned washers or excessive sealant can make a connection harder rather than easier to fit correctly.
Once the plumbing is finished, you'll also need to prevent water from getting between the bath and the surrounding walls. Our How to Seal a Bath guide covers that separate stage of the installation.
How to Test a Bath Waste for Leaks
Don't skip the leak test.
Testing before installing a bath panel gives you much easier access if something needs adjusting.
First, place a dry cloth or piece of kitchen roll underneath each connection.
Add a small amount of water to the bath and check the waste fitting underneath.
Next, close the waste and partially fill the bath. This tests the seal while water is sitting above it.
Release the waste and inspect:
- Waste connection
- Overflow connection
- Bath trap
- Waste-pipe joints
Finally, add enough water to test the overflow and inspect its connections.
If you find moisture, drain the bath and correct the affected connection before continuing.
Never assume a connection is watertight simply because it looks secure.
Can You Fit a Bath Waste Yourself?
If you're comfortable with straightforward plumbing and have good access beneath the bath, fitting a conventional bath waste can be a manageable DIY job.
However, call a plumber if:
- Existing pipework needs significant alteration
- Connections don't align correctly
- You can't identify the source of a leak
- Access underneath the bath is particularly difficult
- You're unsure whether the waste and trap are compatible
- The installation involves plumbing work that you're not confident carrying out
It's much easier to correct a problem while the bath is accessible than after panels, flooring or surrounding finishes have been completed.
Is Installing a Basin Waste the Same?
The basic principle is similar: both involve creating a watertight connection between sanitaryware and the drainage system.
However, the fittings and installation details aren't identical.
If you're working on the basin at the same time, see our separate How to Install a Basin Waste guide rather than applying the bath instructions to both.
Choosing a New Bath
If you're fitting a waste as part of a complete bathroom renovation, make sure the bath itself suits both the available space and how you'll use it.
Our "Finding the Best Bath for Your Bathroom" guide covers the main considerations when comparing bath styles.
Once you've established what you need, explore the complete range of baths from Asturias Bathrooms.
Bath Waste FAQs
Do I need silicone when fitting a bath waste?
Not necessarily. Many bath wastes rely primarily on the supplied rubber washers and seals.
Follow the manufacturer's installation instructions for the specific product. If silicone or another sealant is required, the instructions should specify where it needs to be applied.
How tight should a bath waste be?
The fitting should be tight enough to form a seal and prevent leaks, but shouldn't be over-tightened.
Overtightening can distort washers or damage components.
Why is my bath waste leaking?
Common causes include:
- Incorrectly positioned washers
- Loose connections
- Damaged seals
- Misaligned fittings
- A leaking overflow connection
- A poorly fitted trap
Dry the area thoroughly and test the connections individually to help identify where the water is coming from.
Does a bath waste need a trap?
Yes, a bath normally connects to the drainage system through a suitable trap.
The water retained in the trap creates a barrier that helps prevent drainage-system odours from entering the bathroom.
Can I fit a new bath waste without removing the bath?
Potentially, provided you have sufficient access underneath the bath.
Removing a bath panel may provide enough room on a conventional installation. If the waste is inaccessible, additional work may be necessary.
Should I test the waste before fitting the bath panel?
Yes. Always test the waste, overflow, trap and pipe connections before closing off access.
It's far easier to tighten or reposition a leaking connection while the plumbing remains exposed.
How to Install a Bath Waste: Quick Checklist
Before finishing the job:
- Check that the waste is compatible with the bath.
- Clean the waste and overflow openings.
- Position all supplied seals correctly.
- Secure the waste without overtightening it.
- Connect the overflow.
- Fit the bath trap and waste pipe.
- Check that connections aren't under strain.
- Fill and drain the bath while checking for leaks.
- Test the overflow separately.
- Only close off access once everything is completely watertight.
