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Rear Outlet Toilet : How to Install and Maintain

At some point in your life, you will need to replace a rear outlet toilet. Here are some simple, step-by-step instructions on how to do this (relatively) easy task. Slightly different to install than the wall hung toilet but no more difficult, read on to learn how to make a first class job!

Floor Mounted Rear Outlet Toilet

The floor mount rear outlet toilet has been the most popular choice for many over the years and there is an obvious reason for this. The low purchase cost added to the ease of installation and long life makes the floor mounted rear outlet toilet an excellent choice when renewing your toilet. The availability of these types of rear outlet toilets is without a doubt in abundance with almost all DIY stores stocking a good range of them at attractive prices.

Kohler Rear Outlet Toilet

A popular choice in especially in the United States has to be the Kohler rear outlet toilet and although it’s history generated some negative feedback from buyers of the past this toilet is now one of the leaders for the toilet rear outlet system. Complaints in the past have been mainly related to the noisy operation of the Kohler rear outlet toilet, however these days the manufacturers at Kohler have substantially redesigned their toilet and it is now one of the quietest flushed around.

Rear Outlet Toilet Residential 

Before going out to choose a rear outlet toilet residential for your home it is well worth considering the type of system that suits your bathroom/WC. Many but not all bathroom manufacturers will offer specific colors for the rear outlet toilet residential type and in some cases only white will be available. If you intend to use the new toilet for other than residential use there could be a more suitable choice available for your needs. It is always worth speaking to your chosen supplier about this prior to purchasing.

Rear Outlet Toilet Installation

So what exactly is involved in the rear outlet toilet installation? You will be pleasantly surprised to learn that there is very little work involved and the whole process of rear outlet toilet installation is well within the capabilities of an amateur DIY enthusiast. With a few right tools and some careful preparation you can make an easy job of your rear outlet toilet installation in just a matter of minutes.

Make Sure It Fits!

Measure your current toilet rear outlet, going from behind the toilet to the center of one of the closet bolts which hold the toilet down. Depending on your type of toilet, you could have two or four closet bolts. If the toilet has two bolts, then you will be measuring to about halfway down the bowl; if there are four bolts, then you will be measuring to the rear of the bowl.

Once you're in your favorite home improvement store (such as Home Depot, Menard's, Lowe's, etc.), make sure that any rear discharge toilet you purchase has either the same bolt-to-end measurements (ideally) or is shorter in length. Otherwise, that brand new toilet won't fit in the old spot! Additionally, for really tight bathroom areas, measure your old toilet from its sides so as to insure vertical clearance. You certainly don't want to discover that you can't wedge your new toilet into place because there is a vanity or tub in the way.

Most toilet rear outlet still come as two pieces- the bowl and the tank. Therefore, you will need to pick up two boxes and make sure the components match. You will also need to purchase new closet bolts, a wax gasket, and a toilet seat. It doesn't hurt to pick up a new water supply line too- the new flexible models are far easier to handle and install than the old copper one piece assemblies (which often get broken off during toilet disassembly anyway).

Finally, make sure that the tank has a flush-valve assembly installed inside of it. Most tanks do have one installed, but it never hurts to make sure.

Remove the Old toilet rear outlet

Now that you have the new toilet and its accessories, it's time to remove the old toilet. This is an operation better done in parts than as a whole. In other words, although you could remove your entire toilet as a one piece by just undoing the bolts at the bottom, you will preserve your back, your walls, and your floor much better if you take out the tank first and then the bowl.

To get started, first turn off your toilet's water supply. Most water supplies are located to the rear of the toilet. If no such water valve is found, then you will need to shut off the main water valve. After this is finished, flush the toilet to remove the water in the bowl. Flush again if you can, then use a small cup (and a sponge) to remove the remaining water.

Remove the water supply line from the water valve, unless you plan on reusing it. If you do plan to reuse it, leave it attached to the water valve.

Look inside the tank; there should be a bolt (or two) attaching it to the toilet bowl base. Get a wrench of appropriate size and slowly undo this bolt. Keep in mind that years of water exposure may have rusted out this bolt, making it difficult to maneuver. If this is the case, first try soaking the nut in penetrating oil. Do not try to loosen the bolts by banging on them with your wrench; you will most likely end up cracking the tank and/or seriously hurting yourself. Once your tank is free, slowly lift it and place it somewhere safe and sturdy. Do not prop it against a wall- this will most likely result in it sliding down to the floor, damaging it in the process.

Remove the caps that cover the closet bolts. Take out the closet bolts. Rock the toilet bowl to get it unstuck from its wax gasket. Once it is free, either take it directly outside or place it on an old newspaper or towel. That wax gasket material will be nearly impossible to clean off of any floor if you place the toilet bowl straight down on it.

Using an old and large towel, plug the sewer line that you've just exposed; you don't want sewer gases leaking into the bathroom. Make sure that your towel doesn't fall into the sewer line though! Now, get a putty knife and scrape off the rest of the wax gasket ring, until you can see the mounting flange (it's a ring which keeps the toilet bowl in place and can be made of iron, copper, brass, or even plastic).

Install the New Rear Outlet Toilet: Bowl

Toilets are bolted down to either the mounting flange or the floor. If bolted to the flange, then the closet bolts will probably have flat heads and will slide into the slots on the flange. If the toilet is bolted onto the floor, then the closet bolts will most likely have screw-type threads on one end and bolt threads on the other. The flange, in such a case, does not bear the weight of the bowl.

Insert the closet bolts by either sliding them into the flange, parallel to the wall, or by inserting them in place of the old ones. Now turn your toilet bowl over so that the waste horn is facing you. Take the wax ring you purchased and place it directly onto the waste horn, with the tapered end of the ring facing the toilet. Make sure it is securely attached to the waste horn of the toilet. This often is better performed if the wax ring is warm and soft. If you just brought in your wax ring from the cold, let it warm up first at room temperature.
Unplug your sewer line and position the toilet bowl over it, making sure it is inside of the flange. Put the retainer washers and nuts in place, following the manufacturer’s instructions on their proper installation. Press down gently on the toilet bowl, rocking it into place. Now, tighten the nuts on the closet bolts, alternating from one bolt to the next to insure an even distribution of pressure. Do not over-tighten the bolts, or you may end up cracking the ceramic.

Place the bolt caps over the exposed bolt threads. You may also want to seal the toilet base with a sealant.

Install the New Back Outlet Toilet: Tank

Place the large rubber gasket on the bottom of the rear outlet toilet tank, over its outlet. Insert the tank mounting bolts and associated rubber washers from the inside of the tank. Then, place the tank into position over and behind the toilet bowl. Tighten the tank bolts, again alternating from one bolt to the other to insure even distribution. As before, do not over-tighten the bolts.

Attach the water supply line to the tank underside. A flexible water supply line should just screw into place. A rigid line may require some maneuvering before it fits under the tank. Be careful not to crimp the line as you install it, since this may impede water flow. It may also result in line breakage.
Now you can go and open up your water valve- either the main water valve or the one leading to your new toilet.

Flush It!

After all that hard work, it's time to flush the rear outlet toilet. Just press the lever and watch the miracle of modern plumbing in action. Depending upon the type of flush, you may want to make some adjustments to the amount or speed of water flow. Flush again after you make your adjustments. You're done!


make your adjustments. You're done!