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Toilet Installation Instruction

Toilet Installation Instructions

A Creampuff

Toilets are intimidating plumbing fixtures. Just look inside one. What about the mysterious connection at the floor. Oh, don't forget, there is the supply tube you have to bend just so. Time to call the plumber? Not so fast! You can do it. Toilets are simple.

Connection Components

Residential toilets connect in almost all instances to a three inch drain line. At the floor level, this drain line converts to a toilet flange. This flange is basically a flair fitting that does two things: It provides a way to make a positive air/watertight seal and a way for you to bolt the toilet to the floor. The flange must be a certain distance away from the back wall if you want your toilet to fit snugly against the wall. The standard measurement for most toilets is 12 inches. If a floor joist is in your way, you may need to go 2 inches in either direction (10 or 14 inch). If so, you would need a special toilet bowl. Beware, as these are usually much more expensive. If faced with this situation try what is called an offset flange. It may allow you to use a standard 12 inch toilet.

Click here to watch a toilet flange installation tip video.


A Dry Run

I always want my toilets to be level. As such, I uncrate the bowl (the tank and the bowl are two parts - unless you have a one piece toilet) and simply set it on the flange. Do not use the wax gasket at this point (don't worry, I'll explain!) Set your level across the bowl side to side and front to back. Using shims if necessary, make the bowl level. Gently lift the toilet off the flange keeping the shims in place.

The Wax Gasket & Bolts

A wax gasket is used to make a permanent seal between the flange and the bottom of the toilet. Without this gasket, sewer gas or wastewater would flood your house. They come two ways: with and without a plastic horn. The horn is a simple funnel which directs the wastewater into the flange. I always get a gasket with a horn. Place the gasket onto the flange pointing the horn down into the flange. Now install the new closet bolts that attach the toilet to the flange. Take the bowl, straddle the flange and guide the bowl onto the gasket and the bolts. Be careful!! You only get one chance. Use a friend to help guide you or to position the bolts. The toilet will hit the gasket and seem to rock. Gently push the toilet down to the shims trying to keep it reasonably level. Attach the necessary trim washers, brass washers, and tighten the nuts. Remember, you are tightening against glass so don't go crazy and overtighten!

The Tank

This is the easy part. Reading the toilet instructions you will see that two or thee bolts, rubber washers and brass nuts hold the tank to the bowl. There is a foam washer that fits on the bottom of the tank to provide a seal to the bowl. This is easier than a kid's erector set. As you tighten the tank bolts be sure to level it. It is a breeze.

Supply Tubes

If chrome supply tubes make you pull your hair out, why not use a PVC tube? They bend easily. In either case, once you have the tube attached loosely at the bottom of the toilet and in the valve, tighten the nut up at the tank first. Now, make sure that the tube is leaving the valve squarely. If the tube is at an angle, there is a very good chance you will have a pin hole leak once the compression nut is tightened around the O-ring. This connection is the toughest to make, so take your time. If all goes well, there will be no leaks. However, leaks at compression fittings sometimes show up hours or days later. Put a paper towel under it and check it periodically.


Finish the installation with tile grout. Fill the space between the toilet and floor with grout. Grout up to the shims. Let this grout dry, remove the shims and grout the remaining holes. Total toilet project completion time: One to 1.5 hours!

Local Codes

Now that I have you all pumped up about changing your toilet, you better hold on for just a moment. Certain localities (states, cities, counties) have highly restrictive plumbing codes. In certain areas it is illegal for a homeowner to change out a toilet. Only a licensed plumber is permitted to do it in these areas. So if you want to stay out of jail, you better call your local plumbing department and see just what is permitted in your area. Here in Cincinnati, a homeowner is allowed to perform the job as long as it is inspected. However if you live in Massachusetts, for example, I'm told it is a criminal offense for an unlicensed homeowner to switch toilets. Public sanitation is important, so be sure to check with your local code officials.

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