How to Plumb in a Toilet

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You may be thinking about a new toilet installation for a couple of reasons, whether that be replacing an old one as part of a new bathroom remodelling or because your existing toilet has developed a fault. Most toilet installations are fairly straightforward and can be achieved without the need to employ a professional plumber to do the job. This guide will walk you through the engineering behind a flushing toilet – helping you to understand how they work and diagnose any problems, as well as how to plumb in a toilet yourself. We have also provided you with some essential DIY safety tips and a useful guide on how to make sure your toilet is completely drained of water so that you can remove it without causing too much mess.

Table of Contents

Should you Hire a Professional?

Hiring a professional plumber to install your new toilet could add up to an extra £200 onto the total cost of your bathroom makeover. If this is not a cost you can justify, taking the time to learn how to do it yourself could be a great skill to master. Not only will it save you money now, when you come to redecorate in the future it could come in handy again. When you successfully complete a DIY task, you also get to feel a sense of pride and accomplishment that you just do not get when you pay somebody else to do it for you. There are some cases where hiring a professional is the best course of action. Jobs that you don’t know how to, or don’t feel comfortable doing should be completed by a professional, as well as dangerous jobs that require expert knowledge and experience.

DIY Safety Tips

When you start a new DIY job around the house there are a couple of safety tips you should always keep in mind.

  • Avoid wearing loose clothing or jewellery, and where necessary wear protective clothing, safety masks or goggles.
  • Make sure you have the right tools for the job at hand and check that all tools are in good working order before you use them.
  • Store tools safely away from children and pets.
  • When using a knife always cut away from your body.
  • If you are working with electrics always make sure that the mains supply is switched off first, and that the fuse or circuit breaker has been removed. You should also wear rubber-soled shoes when working on electrical DIY projects.
  • If you need to use an electric drill as part of your DIY project, always remember to unplug the drill before changing parts and to remove the chuck key before operating it.
  • Should you need to use ladders to complete your task you will need to take the right precautions first. When using an A-frame ladder check that they are locked in the open position and placed on a flat, level surface. For leaning ladders, you should ensure that there is a 1 foot spread at the base for every 4 foot of height. Additionally, never use aluminium ladders near electrical wires.
  • Always give yourself enough time to complete your DIY project. If you are rushing you are at risk of making mistakes or even injuring yourself.

The Parts of a Toilet

Understanding how your toilet works will help you diagnose any problems with your loo and keep it properly maintained. A simple device, the flushing toilet is an easily installed system that does not need any complicated electrical systems or motors to work. Most homes are installed with similar toilets that contain similar parts which can easily be found in DIY shops and hardware stores. The handle and flush rod are the parts of the toilet responsible for the flushing of the toilet. The handle is connected to the rod, which in turn is connected to a chain or wire. The next part that comes into play is the lift chain. This chain controls the flush valve at the bottom of the tank and when operated opens the valve, letting the water sitting in the tank flush down into the toilet bowl. If the lift chain becomes broken or tangled it will mean the toilet does not flush at all and the chain will need fixing or replacing. The water supply valve (also known as the ball cock) controls the freshwater supply that feeds into the tank to refill it after a flush. The supply valve closes off once the float cup (or float ball) detects that the water level is at the right height. However, the supply valve can be prone to wear and tear and may need fixing or replacing – a common problem with toilets over time. When engaged, the lift chain lifts a flapper (or tank ball) off the flush valve, allowing the water to fall into the toilet bowl. Flappers can fall victim to wear and tear or become misaligned over time which allows the water from the cistern to continually leak into the toilet. If you notice your toilet is always running you will need to replace the flapper. The flush valve sits at the bottom of the cistern and is the opening through which the water flows out and into the toilet bowl. The flush valve is connected to the tailpiece leading from the tank to the bowl with an O-ring seal, it is also connected to the vertical overflow tube. The overflow tube is installed as a safety precaution to stop water gathering and overflowing in the cistern if the water supply valve fails. The excess water will spill over the top of the overflow tube and into the toilet bowl. If you notice that your toilet seems to always be running, the water level could be too high in the tank. The shutoff valve helps to control the cold water that feeds into the toilet from the water supply pipe. This valve will cut off the water supply when you need to make repairs to your loo, or if you are removing it. The shutoff valve feeds into the supply tube – a plastic or wire mesh tube. The refill tube is attached to the top of the overflow tube in the middle of the tank and sends a small amount of water into the bowl to refill it after it has been flushed. The toilet bowl is bolted to the floor and is kept filled with water to seal it against sewer gasses. The toilet bowl contains a hidden curved trap that holds water and is the most common cause of blockages. Finally, a wax seal ring is used to seal the connection between the bottom of the toilet and the drain opening in the floor. The wax seal creates an airtight and water-tight seal between the toilet and the sewer line. If you notice water leaking from the bottom of the toilet when it is flushed, it will be because the wax seal has failed and needs to be replaced.

Important Things to Remember Before Installing a New Toilet

Before you begin thinking about replacing a toilet you’ll first need to shop for a new one. However, remember that to get an accurate measurement and find the right size toilet you will need to measure from the wall behind the toilet to the two screws in the base of the old toilet that hold it to the floor. The average distance is 12 inches but if you find that it is longer or shorter, you’ll need to bear this in mind when shopping for a new model. A toilet can be purchased as a complete unit including the base and the tank, or you can choose to buy these separately. Toilet bases also come in different heights, and you can choose if you want the toilet to be rounded or elongated. When installing or removing a toilet always handle with care, a toilet is made from porcelain and can easily break if excessive force is applied. Before removing an old toilet, you may also want to clean it with an antibacterial solution to make your job a bit more pleasant! If you are renovating your bathroom and intend to put down new tiles, you will need to allow time for them to fully set before you plumb in your new toilet.

Tools You Will Need

To plumb in your new toilet, you will need the following tools:

  • Wrenches
  • Screwdrivers
  • Silicone
  • Adjustable pliers
  • Pipe Cutter or Hacksaw
  • Pipe Wrench
  • Box Spanner
  • Hammer
  • Spirit Level
  • Drill
  • Tape Measure
  • Pencil
  • Bucket
  • Towel

How to Fully Drain a Toilet

When removing an old toilet, you will need to make sure that it is fully drained before you can take it out and transport it. However, because the toilet constantly has water running through it, it can be difficult to ensure that it is fully dry when you come to uninstall it. There is also a trap at the bottom of the toilet bowl that clings onto water, even when you think you have completely drained it. The steps below will help you to fully drain your toilet of water, making your DIY toilet removal and installation as mess-free as possible. The method below uses the toilet’s shut off valve, however in some cases the valve may have stopped working especially if it is an old valve. If you follow the steps and notice the water is still running you will have to shut off the main water supply before you can drain the water from the toilet. Flushing the Toilet After Turning Off The Water Supply The first thing you need to do is to turn off the water supply and flush the toilet to remove most of the water. To do this, locate the shut off valve – this is usually found where the water supply pipe appears from the wall or floor. The supply pipe is connected to a supply tube that leads to the toilet’s supply valve. Turn the valve clockwise until it stops turning and then flush the toilet holding down the handle until the cistern and bowl are as empty as possible. At this stage, you may notice that there is a small amount of water left, so take a sponge and soak up the remaining water from both the bowl and the cistern. Using a Plunger If your toilet is clogged and the water cannot flush without flowing over the bowl you will need to use a plunger to help. Once you have shut off the water supply valve, take a plunger and place it firmly into the drain hole at the bottom of the toilet. Then, using an up and down motion, plunge slowly to force the water through the drain – this should also clear out any clogs in the drain. If you have successfully removed the clog, the water should now flow freely through the drain so you can flush the toilet to empty the cistern. If you have a lot of water remaining, use the plunger to force it through the drain hole, and use a sponge to soak up and residual water after this. Siphoning the Water Another method you could try when emptying the water from the toilet is the siphoning method. For this, you will need a short flexible hose, rubber gloves and a bucket large enough to carry the water from the toilet. Please be aware that this method will only work if there is no toilet paper or other debris in the toilet bowl. First, fill up the hose completely with water and cover both ends with your thumbs so that no water escapes or air gets in. If air does get in, it will break the siphon so you will need to start again. Place one end of the hose into the toilet bowl (or the cistern) and direct the other end into the bucket (the bucket must be lower than the surface of the water in the toilet bowl). When you are ready, release both ends of the hose and the water will start to drain from the toilet into the bowl. It will continue draining as long as the end in the bowl is kept submerged underwater and the bucket is kept lower than the toilet bowl. Manually Bail Out The Water You could also choose to manually bail out the water using a cup or a small bowl. If you follow this method, you will need to use an implement small enough to get into the bottom reaches of the bowl and to empty the water from the toilet trap. Vacuum The Water Out If you have a wet-dry vacuum, you could quickly vacuum the water out of the toilet bowl and tank. Only do this if the water is clean though and do not overfill the vacuum with water as it could become too heavy to move when you are finished. Sponging away The Water Whichever method you employ to remove the main body of water, you will also need a sponge to get rid of the small amount of water remaining at the bottom of the bowl or the bottom of the cistern. Choose a large, absorbent sponge and wear rubber gloves to protect your hands from any bacteria that may be lurking within the toilet. Once you have absorbed the water, you will need to squeeze it into an empty bucket that can be taken away.

Removing Your Old Toilet

Whether you are renovating an old bathroom with a new suite or changing your floor tiles, removing a toilet is not too difficult a task. Our guide will walk you through the correct procedure to follow when uninstalling a toilet.

  1. Turn off the water. The first thing you will need to do is turn off the water supply to the toilet and make sure the bowl is completely emptied. To do this, use the isolation valve on the toilet to turn off the water supply and then flush the chain until the toilet is completely emptied of water. You should notice that the cistern does not refill after you flush if you have turned off the water correctly.
  2. Disconnect the water pipe. The cistern on the toilet is connected to the water supply through a water pipe. To disconnect this pipe, take a wrench to undo the fittings and remove the pipe from the cistern. There could be some water still sitting in the pipe so be prepared for a small spillage that you may need to mop up with your towel.
  3. Remove the fixing bolts. Your toilet base is held in place with several bolts screwed into the floor and there may also be silicone. You will need to loosen these bolts and scrape away the silicone to move the toilet.
  4. Remove the toilet from the soil pipe. Also known as the waste pipe, the soil pipe sits at the back of your toilet. Gently work the toilet base free from the pipe and lift it away.
  5. Finally, cover up the opening of the soil pipe to stop harmful and unpleasant smelling gasses from being released into your bathroom. This is also a good time to check the soil pipe for wear and tear and to replace any parts that have become corroded before you install your new toilet.

Disposing of Your Old Toilet

Once you have removed an old toilet you will need to dispose of it responsibly at your local household waste recycling centre (also known as a tip). Before you transport the toilet to the tip for recycling, you will first want to make sure that it is clean and dry to avoid soiling your house or car. It is also worth calling ahead to check that the tip will accept the toilet before you make the journey there. Some tips also will not allow vans or large vehicles to dispose of waste, or a charge may be applied to these types of vehicles.

Plumbing in Your New Toilet

Plumbing in a toilet isn’t a difficult task with the right guidance. The main thing to keep in mind is to check that all of the seals are watertight and secure. This guide is suitable for all of the main pan styles of a toilet, however, always refer to the manufacturers’ instructions before you install your new toilet. Installing a New Toilet Into an Existing Location The following steps apply to toilet installations into an existing location, attaching to a soil pipe and water supply already in place.

  1. Your first task is to measure and mark the drill holes that you will need for the bolts to secure your toilet.
  2. You will need to add the new wax ring to the soil pipe next, ready for the new loo. When this is in place go ahead and attach the toilet to the soil pipe.
  3. Next, its time to screw in the bolts that will hold the toilet in place. Start by screwing the bolts in half at first and then carefully tighten them. Do not over tighten these bolts as you are at risk of cracking the toilet pan if you do.
    1. If your toilet is held in place with an L-shaped bracket you will need to follow a slightly different route here. First, fit the toilet to the soil pipe and push it back into position, then with a pencil mark on the floor where the holes are. Once you have done this disconnect the toilet from the soil pipe and turn it upside down. Then, loosely put the screws into the L-shape bracket and measure the distance between the two holes and divide this by 2.

3.2 Measure the markings on the floor and divide this by 2 and then find and mark the centre of the two markings on the floor.

  1. Using the measurement from between the two L brackets, mark outwards from the centre towards the original floor markings.
  2. Carefully mark these positions on the floor – this is where the L-shape brackets will be fixed in place.
  3. Screw the brackets in place, using the new markings.
  1. The next step is to install the cistern. There different types of cisterns but the most common ones are close-coupled cisterns, high-level cisterns, low-level cisterns, or concealed cisterns. If you have a toilet with a concealed cistern you will likely need professional help to install it.
    1. To install a close-coupled cistern you will need to begin by slotting in the bolts that hold the cistern to the top of the toilet. There are usually two bolts with square ends that will fit into spaces on either side of the seal on the underneath of the cistern. Next, look for a hole in the top of the toilet pan where the water passes from the cistern to the pan when flushed. Place the seal on top of this hole and carefully position it over the pan, taking care to make sure all of the screws line up. Once you are happy with the positioning, tighten all the screws to hold the cistern to the pan. You will also need to fix the cistern to the wall once you have done this to keep it in place.
    2. If you are installing a low level or high-level cistern, you will need to follow the steps outlined next. The installation process for these types of cisterns can vary between manufacturers so always refer to the handbook, and if you are unsure at any point do not hesitate to call in a professional plumber. As a general guideline, you will need to measure your cistern against the wall and mark out the right places to drill holes for the bolts. Line the piping lines up with the cistern and use a spirit level to keep the cistern level. If you are installing the toilet from scratch and it has a high-level or low-level cistern you will probably need to enlist the help of a professional to make sure the water supply pipe is correctly installed.
  2. Once the cistern has been installed the next job is to connect the water pipe using a wrench. Make sure the water pipe is firmly connected so it doesn’t spring any unexpected leaks. The new toilet should come with all of the nuts and washers needed but you could also add some extra silicone where the bolts meet the cistern for an additional level of protection.
  3. Check for leaks. Once you are satisfied that everything is connected as it should be, its time to turn back on the water supply and test the toilet for leaks. Wait for the cistern to fill and then flush the toilet checking for leaks. Remember to check around all of the seals and fittings – you may want to keep a towel handy in case there are any surprise leaks.

Moving a Toilet to a New Location

When remodelling a bathroom, you may want to move your toilet to a new location which will involve moving the drainage and water supply plumbing as well. Moving the location of the toilet involves some more advanced plumbing work but it can be achieved without having to bring in a contractor to do the job. To move the toilet, you will need access to the drainage pipes that lie under the floor and the water supply pipes that are found within the walls. What Tools Will You Need? The following tools and equipment are required for moving the location of your toilet:

  • Flathead screwdriver
  • Gloves
  • Prybar
  • Putty knife
  • Circular saw
  • Reciprocating saw
  • Cordless drill
  • Toilet
  • 6-feet of 3-inch drainpipe, PVC or ABS
  • 1/2-inch PEX pipe, 8 feet
  • Push-fit or compression ring PEX fittings
  • Toilet closet flange
  • 3-inch diameter long-sweep 90-degree bend, ABS
  • 3-inch wye drain fitting, ABS
  • 3-inch 90-degree bend, ABS
  • ABS glue

Moving the Toilet Drainage

  1. The first task is to remove the toilet (follow the steps above to achieve this) If you intend to reuse the same toilet instead of replacing it with a new one, carefully move it out of the way and store it somewhere safe to avoid breakages.
  2. You will then need to gain access to the underfloor toilet drainage lines. There are two ways that you can do this; either by going under the floor of the bathroom or if you have access from the room below you could choose to go through the ceiling.
  3. Using a screwdriver, unscrew the toilet flange from the floor and remove it from the drain pipe. In some cases, the flange may be cast iron so it will need to be broken up with a hammer first.
  4. Locate the toilet bend and, using a reciprocating saw, carefully cut away the bend as closely as possible to the waste vent sack.
  5. Following this, you will need to find a new location for the toilet drain. When installing the new drain keep in mind that there should be 15 inches of space from the centre of the drain to all side walls including the shower and the bathtub.
  6. Once the drain is in place, take the new length of drainpipe and run it from the relocated drain location to the waste vent sack. You should use a straight length of pipe that runs into the long sweep 90-degree bend.
  7. Attach the bend to the waste vent stack with a new wye, and make sure that you are using ABS approved glue to hold all ABS materials together. To ensure a good flow, the drain line should slope at least a quarter of an inch or more down for every horizontal foot towards the stack. Make sure the pipe is fully supported using straps along the length of it.
  8. Continue installing the toilet drain by glueing the ABS 90-degree bend onto the end of the drain and adding a six-inch length of pipe onto the top – support this where necessary.
  9. Next, turn your attention to the water supply lines. You can continue the original water supply by adding a length of PEX pipe through the joists. When you get to the new toilet location bring the water supply up through the wall and finish it with a turn valve that you have left exposed through the wall.
  10. After you have done this, replace the subfloor and finish the flooring. Cut off the drain pipe flush with the level of the floor and install the toilet flange on top of the floor by screwing it in place.
  11. Finally, install the toilet in its new location, turn the water supply back on and test the toilet by flushing it. Remember to check for any leaks that could pose a problem in the future.

All in all, your toilet installation project should take between one to four hours depending on how much work needs to be done and the type of toilet you are installing. Always remember to consult a professional plumber if there are any aspects that you are unsure of.