How to Replace a Broken Toilet Flange

Begin by turning off the water to the toilet using the shutoff valve located on the wall behind it. Turn the handle clockwise until it stops. Flush the toilet to empty the tank and hold the handle down to drain as much water as possible from the bowl. Use a sponge and bucket to remove any remaining water from the tank and bowl. Disconnect the water supply line from the base of the toilet tank using an adjustable wrench. Finally, pry off the plastic caps at the base of the toilet, unscrew the nuts from the closet bolts, and with a helper, carefully lift the toilet straight up and set it aside on some old towels or cardboard.

With the toilet removed, use a putty knife to scrape the old wax ring off the flange and floor. Dispose of the wax. Stuff a large rag into the drain pipe opening to block sewer gases and prevent tools from falling in. Assess the broken flange. Remove any screws holding it to the subfloor with a drill or screwdriver. If the flange is PVC and glued to the pipe, you may need to carefully break it away from the pipe using a hammer and a small chisel. Work cautiously to avoid damaging the drain pipe itself. Pry the broken pieces away with a pry bar until the top of the drain pipe is fully exposed and accessible.

Now that the area is clear, thoroughly inspect the subfloor surrounding the drain pipe. Use a flashlight to look for signs of water damage, such as dark stains, discoloration, or delamination of plywood. Probe the wood with the tip of a utility knife or a screwdriver; if it feels soft, spongy, or crumbles, it has rotted and must be repaired. Assuming the subfloor is solid, ensure the surface is clean, dry, and free of any old sealant or debris to provide a flat, stable base for the new flange.

Select a new PVC toilet flange that is designed to fit over the outside of your 3-inch or 4-inch drain pipe. First, perform a 'dry fit' by placing the new flange over the pipe to ensure its base sits level and flush with the finished tile floor. The top of the flange should be no more than 1/4 inch above the floor. Once you confirm the fit, apply a liberal coat of purple PVC primer to the outside of the drain pipe and the inside socket of the new flange. Immediately follow this by applying a generous layer of PVC cement over the primed areas. Firmly press the flange down onto the pipe, giving it a slight quarter-turn twist to spread the cement evenly. Ensure the closet bolt slots are positioned correctly (parallel to the back wall). Finally, secure the flange to the subfloor by driving corrosion-resistant screws through the provided holes into the solid wood.

First, and most importantly, REMOVE THE RAG from the drain pipe. Insert the new closet bolts into the slots on the new flange, sliding them into position (typically at the 3 o'clock and 9 o'clock positions). Place the new wax ring on the flange, centered over the opening, or press it firmly onto the circular outlet horn on the bottom of the toilet. With your helper, carefully lift the toilet and lower it straight down over the flange, aligning the closet bolts through the holes in the toilet's base. Press down firmly on the toilet bowl to compress the wax ring and create a seal. Place the plastic washers and metal washers onto the bolts, followed by the nuts. Tighten the nuts by hand, then use a wrench to tighten them alternately, a half-turn at a time, until the toilet is snug and stable on the floor. Do not overtighten. Reconnect the water supply line to the tank.

Slowly turn the water shutoff valve counter-clockwise to turn the water back on. Listen for the tank to fill. Once it stops filling, inspect the water supply line connection at the tank for any drips. Flush the toilet completely. As the bowl refills, use a flashlight and dry paper towels to meticulously check for any signs of water leaking from around the base of the toilet. Wipe the entire perimeter where the toilet meets the floor. If the paper towel stays dry, the seal is good. Flush several more times to be certain. If no leaks are detected, the project is complete. Clean up your tools and materials.