How to Install a Mixer Tap and Waste

Ready to give your bathroom basin or kitchen sink a fresh, modern look? Installing a new mixer tap and waste is a fantastic way to upgrade its style and functionality. While it might seem daunting, it's a very achievable DIY project for someone comfortable with basic plumbing tasks.

Here at Plumbers Choice, we're not just about supplying top-quality taps and wastes; we want to give you the confidence to fit them too! This guide will walk you through the process step-by-step.

Is This DIY Project Right for You?

This project involves working under the sink, disconnecting and reconnecting water pipes, and ensuring watertight seals. If you're comfortable using spanners and understand how your water supply works, you should be fine. If you're unsure at any point, it's always best to call a qualified plumber.

Safety First! Always!

• Turn Off the Water: Before you do anything else, shut off both the hot and cold water supply to the old tap. Look for isolation valves (small levers or screws on the pipes directly below the tap) and turn them 90 degrees. If you don't have these, you'll need to turn off your home's main water supply via the stopcock (usually under the kitchen sink or where the water pipe enters your property).
• Drain the Pipes: Turn the old taps on to drain any remaining water from the pipes.
• Prepare for Spills: Place an old towel or bucket under the basin to catch any drips.

Tools & Materials You'll Need:

• Your shiny New Mixer Tap (check it comes with flexible tap tails and fixing kit)
• Your New Basin Waste (e.g., click-clack, pop-up, free-running – ensure it matches your basin type: slotted for basins with an overflow, unslotted for those without)
• Basin Wrench or Tap Spanner Set (essential for tightening nuts in awkward spaces)
• Adjustable Spanners (various sizes)
• Pipe Wrench (potentially needed for stubborn old fittings)
• Silicone Sealant (plumber's grade, sanitary quality)
• PTFE Tape (for threaded pipe joints, not usually needed for the flexible tap tail connections themselves if they have rubber washers)
• Bucket & Old Towels/Cloths
• Screwdrivers (may be needed for removing old fixings)
• (Optional) Pipe Cutter, Compression Fittings, Flexible Hoses (if existing pipework needs modification)

Step-by-Step Installation Guide

Part 1: Removing the Old Tap and Waste

1. Disconnect Tap Tails: With the water off, use adjustable spanners to disconnect the old tap connectors (tails or rigid pipes) from the hot and cold water supply pipes. Be ready for a little residual water.
2. Undo Tap Fixings: Look under the basin. The old tap is usually held by a large nut or a threaded stud with a smaller nut and shaped washer/plate. Use your basin wrench or tap spanner to undo this. It can be fiddly!
3. Lift Out Old Tap: Once the fixings are removed, carefully lift the old tap out from the top of the basin.
4. Disconnect Waste Trap: Unscrew the coupling(s) connecting the bottle trap or P-trap to the bottom of the old waste fitting. Pull the trap away.
5. Undo Waste Fixing: The old waste is held by a large retaining nut on the underside of the basin. Unscrew this (a pipe wrench might help if it's stiff).
6. Remove Old Waste: Push the waste up and out from the top of the basin.
7. Clean Up: Thoroughly clean the tap hole(s) and the waste hole in the basin, removing any old sealant or grime.

Part 2: Installing the New Mixer Tap

1. Prepare the Tap: Screw the flexible tap tails into the base of your new mixer tap, if they aren't pre-fitted. Usually, these tighten by hand, followed by a gentle nip with a spanner – check the tap instructions. Feed the fixing stud(s) into the tap base too.
2. Position the Tap: Feed the flexible tails and fixing stud(s) through the tap hole in the basin. Ensure any supplied rubber gasket or base plate is correctly positioned between the tap and the basin surface.
3. Secure From Below: From underneath the basin, slide the supplied rubber washer (if applicable) and then the metal fixing washer/plate over the stud(s). Screw on the retaining nut(s).
4. Align and Tighten: Check the tap is straight and properly aligned from above before fully tightening the nut(s) underneath with your basin wrench or tap spanner. Get it firm and secure so the tap doesn't wobble.
5. Connect Tap Tails: Connect the end of the hot flexible tail to the hot water supply pipe and the cold tail to the cold supply. Use appropriate fittings (often the tails screw directly onto isolation valves or standard 15mm compression fittings). Crucially: The connections on flexible tails usually seal via internal rubber washers – do NOT wrap PTFE tape around these threads unless the instructions specifically say to. If connecting to existing bare pipework, you may need compression fittings – use PTFE tape on the thread of the compression fitting itself where it screws together (not on the pipe or olive).

Part 3: Installing the New Waste

1. Prepare the Waste Flange: Check the waste instructions. Some come with a soft rubber/foam washer to seal the top flange inside the basin. Others rely on a bead of silicone sealant applied to the underside of the flange before you insert it. Silicone generally gives a reliable seal.
2. Insert the Waste: Apply sealant or position the top washer, then push the main body of the waste down through the basin's waste hole.
3. Seal From Below: From underneath, fit the large rubber sealing washer onto the threaded part of the waste body, ensuring it sits flat against the underside of the basin ceramic.
4. Tighten Retaining Nut: Screw on the large plastic or metal retaining nut. Hand-tighten first, then use a wrench or grips for a final firm tighten. Don't overtighten, especially with plastic nuts, but ensure it's sealed. If you used silicone, wipe away any excess neatly from inside the basin immediately.
5. Reconnect Trap: Re-attach the waste trap (P-trap or bottle trap) to the bottom of the new waste fitting, ensuring any rubber seals within the trap couplings are present and correctly seated. Tighten the trap couplings firmly by hand.

Part 4: Testing Time!

1. Double-Check: Quickly go over all the connections you've made – tap tail connections, tap fixing nut, waste retaining nut, trap connections. Ensure they feel secure.
2. Turn Water On Slowly: Go back to your isolation valves or main stopcock. Turn the cold water back on slowly, checking immediately for any drips or spurts from the cold tap tail connection or the tap body itself. Repeat for the hot water.
3. Inspect Thoroughly: With the water pressure back on, carefully inspect every joint under the basin for leaks. Use a dry cloth or paper towel to wipe each joint – it makes spotting tiny drips easier.
4. Run the Tap: Turn the new mixer tap on. Check the flow of hot, cold, and mixed water.
5. Test the Waste: Close the new waste (if it's a pop-up or click-clack type) and let some water fill the basin. Check the waste seal inside the basin isn't leaking. Then check the waste body underneath and the trap connections for leaks as the water sits. Finally, open the waste and check again as the water drains away.
6. Final Check: Leave it for an hour or so, then perform one last visual check underneath for any slow drips you might have missed.

Success!

Congratulations! You've successfully installed your new mixer tap and waste, giving your basin a whole new lease of life. Step back and admire your handiwork!

Need parts for your next plumbing project? From stylish taps and wastes to all the essential tools and fittings, find everything you need right here at Plumbers Choice.