How to Install a Toilet

As you prepare to install a new toilet in your remodeled or brand-new bathroom, it's good to address some terminology that will make it easier to purchase parts you might need as well as the new toilet itself. Plumbers officially refer to a toilet as a "water closet," a term that hearkens back to the days of the special room into which English aristocrats retired to do their business. The entire room was also sometimes called a "toilet."

According to John C. Flood of VA Inc., it wasn't until the turn of the 20th century — not that long ago — that modern bathroom plumbing became commonplace, and people began using the term "toilet" for the actual sanitary fixture itself. Since the term had originally been interchangeable with "water closet," the correlation has persisted, and plumbers still refer to it that way as well as calling the bolts used to hold the toilet to the floor "closet bolts" and the drainpipe fitting just under the toilet the "closet flange." That's the terminology you'll find in all the plumbing codes.

DIY plumbing know-how is more important than words when it comes to installing a toilet, but you don't need an overabundance of skill because toilets are designed for easy installation, and not much can go wrong. Every toilet has a standard toilet base that fits on a closet flange, which is also more or less standard, and the water connection also varies little from bathroom to bathroom. The only difficulty you might encounter would be caused by a closet flange that's mounted too far above the floor surface or recessed too deeply below it.

If you're replacing an old toilet, you'll have an old closet flange before you that is probably caked with leftover wax from the previous wax ring. Clean off as much wax as possible wearing rubber gloves and using a putty knife and disposable towels. Examine the flange carefully. Since it's old, it's probably made of cast iron, and it may have partially corroded. If so, it might not be able to hold the closet bolts for the new toilet for long if at all.

Replacing an old flange is a big job that you don't want to do, and in most cases, you don't have to do so. Depending on the extent of the damage, you can repair a corroded flange with a flange bracket or an entire repair ring that you bolt to the subfloor. A flange repair bracket or ring offers a secure anchor for the closet bolts, but it often adds enough thickness to the flange to lift the toilet off the floor, so you might have to be ready to shim the base of the toilet to prevent rocking.

Another problem you might encounter during a home improvement project that includes a new bathroom floor covering is that the flange sits too far below the surface of the new floor for the wax ring to make contact. To prevent a leak, install a flange extender, which is like a repair ring but thicker and made of plastic. Use one that is thick enough to bring the surface of the flange to within 1/4 inch of the floor surface to guarantee a good wax seal.

When you purchase a new toilet at a plumbing supply outlet, a home improvement center or an online source such as Amazon, it usually comes with everything you need to install it except for the tools. Most toilet kits include the toilet bowl, toilet tank — including the flush and fill valves — tank lid, closet bolts, tank bolts, a rubber gasket that goes between the tank and the bowl (sometimes called a spud), a seat cover with plastic bolts and a wax ring.

The seat cover provided with most toilet kits is made of cheap plastic, so while you're at the store you may want to consider purchasing a more decorative and sturdy one. You may also want to buy a waxless toilet gasket, such as a Sani Seal foam ring or a Danco rubber gasket, to use in place of the wax ring supplied with the toilet. You seldom need a wax ring thicker than a standard one, as Tracey Fitz discovered. If the closet flange is elevated above the floor, you'll also need plastic toilet shims to prop up the base of the toilet.

One more thing you'll need is a braided, metal, flexible connector to connect the toilet tank to the water supply valve. Toilet tanks have a standard 3/4-inch male threaded inlet, but the outlet on the shutoff valve could have 3/8- or 1/2-inch male threads, so be sure to get the right connector. It's also a good idea to measure the distance of the supply valve from the toilet so you get a connector that isn't too short or too long.