Installing a New Toilet from Scratch

Pre-Installation Preparation

Before purchasing a new toilet, measure the rough-in distance — the measurement from the finished wall to the center of the closet bolts (not from the baseboard). The standard rough-in is 12 inches, but 10-inch and 14-inch rough-ins exist in some homes. Also confirm the water supply connection location and type. Choose a toilet with a MaP rating of at least 500 grams for reliable solid waste removal. Elongated bowls are more comfortable but require more space; round bowls are better for tight bathrooms.

Setting the Wax Ring and Bowl

If replacing an existing toilet, remove it following proper procedures and clean the flange thoroughly. Insert new closet bolts into the flange slots, centered equidistant from the wall. Place the wax ring on the flange (standard or extra-thick, depending on the floor height relative to the flange). Carefully lower the toilet bowl straight down, aligning the bolt holes with the closet bolts. Press down with your full body weight to compress the wax ring. Alternate tightening the closet bolt nuts until the toilet is firmly seated — do not over-tighten. Check that the toilet does not rock. Apply shims if needed, then caulk the base.

Attaching the Tank

For two-piece toilets, place the rubber spud gasket on the flush valve nut at the bottom of the tank. Insert the tank bolts with rubber washers through the tank bolt holes. Carefully lower the tank onto the bowl, aligning the bolts with the bowl mounting holes. From underneath, thread brass washers and nuts onto the bolts and tighten alternately until the tank sits level and snug on the bowl. Do not over-tighten — the rubber gasket should compress just enough to seal without cracking the porcelain.

Final Connections and Testing

Connect the water supply line to the fill valve tailpiece at the bottom of the tank — use a braided stainless steel supply line for reliability. Turn on the water supply slowly, watching all connections for leaks. Let the tank fill and check the water level — adjust the float to set the level to the manufacturer's recommended line. Flush the toilet several times and inspect all connections. Check for rocking or instability. Install the toilet seat according to the provided hardware. Caulk around the base with a continuous bead of silicone, leaving a small gap at the back to allow water from a potential future leak to be visible rather than hidden.