Step-by-Step Guide: Installing Your New WC Unit in Your Bathroom

A WC unit is an important fixture in a modern bathroom, providing both functionality and style. However, ensuring correct installation for optimal performance, safety, and hygiene is crucial. 

This guide provides step-by-step instructions for installing a WC unit, covering material selection and installation. 

Brief Overview of the Installation Process 

Installing a WC back to wall toilet unit involves several key steps. These include:

  • Preparing the bathroom space
  • Positioning the unit
  • Connecting the waste pipe and drain     
  • Fixing the unit securely to the wall  
  • Installing the toilet cistern, toilet seat, and flush mechanism

You will need to carefully follow each step outlined in the installation guide for optimal functionality of your bathroom.

500mm Hale Black WC Unit & Back To Wall Toilet With Seat And Cistern

Tools and Materials Required for WC Unit Installation 

List of Essential Tools and Materials 

Here is the list of essential tools and materials needed for your WC unit installation. 


  • Tape measure
  • Spirit level
  • Adjustable wrench
  • Hacksaw
  • Screwdriver
  • Drill and drill bits
  • Pliers
  • Rubber gloves
  • Caulking gun
  • Bucket and sponge
  • Adjustable spanner


  • WC toilet unit with cistern and flush mechanism
  • WC cistern and flush mechanism
  • Toilet Bowl, seat, and lid
  • Waste pipe
  • Mounting screws and brackets
  • Silicone sealant
  • Water supply pipe and valve
  • Cleaning and sanitizing solution
  • Teflon tape
  • Bolts and nuts
  • Wall plugs

Tips for Gathering Necessary Items

  • Research online or consult with a professional plumber to gather, find, and buy the necessary items for a DIY WC toilet unit installation.
  • Determine the required items and create a list of everything you need with measurements and specifications.
  • Shop around to find the best deals at multiple retailers and online stores.
  • Look for reputable sellers with good customer reviews and a return policy.
  • Take note of delivery costs and estimated shipping times.
Modena 500mm Satin Blue BTW WC Unit With Rimless Toilet Seat And Various Pans

Preparing Your Bathroom for WC Unit Installation 

Removing the Old Toilet (if Applicable) 

  • Turn off the water supply and disconnect the water supply line.
  • Remove the tank, bowl, and wax ring.
  • Cap the waste pipe.
  • Clean the area thoroughly.

Preparing the Bathroom Floor and Walls

  • Clean and level the bathroom floor and walls to prepare for installing a WC toilet unit.
  • Install a flange on the waste pipe and cut a hole in the subfloor.
  • Apply sealant before installing the drainpipe.
  • Install any necessary support brackets for stability.

Step by Step Guide to Installing a WC Unit

Assembling the WC Unit

  1. Unpack all components and check against the manufacturer's instructions.
  2. Install the rubber gasket onto the flange, followed by the wax ring and mounting bolts.
  3. Place the bowl onto the mounting bolts, ensuring it is level, and tighten the nuts.

Attaching the Cistern

  1. Install the rubber gasket onto the cistern and place it onto the bowl.
  2. Connect the bolts and tighten them, making sure the cistern is level.

Connecting the Water Supply

  1. Connect the water supply line to the fill valve and turn on the water to fill the cistern.
  2. Check for leaks and adjust the water level as needed.

Installing the Toilet Pan 

  1. Apply a bead of sealant to the rim of the pan.
  2. Place the pan onto the waste pipe and press down firmly.
  3. Connect the waste pipe to the pan using the provided fittings.

Securing the WC Unit to the Wall and Floor 

  1. Use the provided screws to secure the cistern and pan to the wall.
  2. Install any necessary brackets to secure the unit to the floor.

Finalising the Connections and Testing

  1. Tighten all connections and check for leaks.
  2. Test the flush and adjust the water level as needed.
  3. Install the seat and lid as per the manufacturer's instructions.

 Post Installation Tips and Maintenance

Ensuring Proper Function of the WC Unit

  • Check for any leaks or malfunctions in the system after installation.
  • Ensure the flushing mechanism is working properly and adjust as needed.

Ongoing Maintenance and Care

  • Clean the bathroom WC unit regularly to prevent build-ups of bacteria and germs.
  • Use only recommended cleaning products to avoid damaging the unit.
  • Check for any signs of wear or damage and repair as needed.
Modena 500mm Satin White BTW WC Unit With Rimless Toilet Seat And Various Pans


Installing a WC toilet unit is a challenging yet rewarding DIY project. 

Proper planning, research, and preparation are crucial for success. Following our step-by-step and taking safety precautions will ensure a stable and functional WC unit.  Don’t forget the ongoing maintenance and care to ensure longevity and prevent malfunctions or leaks.