What is inside the tank
- Fill valve
- The upright valve on one side of the tank that refills it after each flush and shuts off when a float rises.
- Float
- A cup or ball attached to the fill valve that rises with the water and tells the valve when to stop.
- Flush valve
- The large opening at the bottom center of the tank where water drops into the bowl.
- Flapper
- The rubber seal that covers the flush valve opening and lifts when you press the handle.
- Overflow tube
- The open tube beside the flush valve that sends excess water to the bowl if the fill valve does not stop.
- Refill tube
- A small hose from the fill valve into the overflow tube that tops up the bowl after a flush.
How each part fails
Fill valve
- Hisses or trickles after the tank is full
- Fills slowly or not at all
- Water spills into the overflow tube
- Sediment or mineral scale fouls its seal
Flapper
- Lets water seep into the bowl, causing phantom refills
- Warps, stiffens or swells with age
- Closes too early, weakening the flush
- Chain tangles or catches under the edge
How a flapper replacement usually goes
Shut off and flush
Close the shutoff valve and flush to empty the tank.
Unhook the old flapper
The flapper clips onto pegs on the overflow tube or slides over it, and the chain unhooks from the handle arm.
Clean the seat
Wipe the flush valve rim where the flapper sits. Mineral scale or a rough spot here can keep any flapper from sealing.
Fit the match
Install a flapper sized for the flush valve and set the chain with a small amount of slack.
Refill and test
Open the valve, let the tank fill, and do a dye test to confirm the seal.
How a fill valve replacement usually goes
Drain the tank
With the water off, the tank is flushed and the remaining water sponged out.
Disconnect the supply
The supply line nut under the tank is loosened, with a towel ready for drips.
Swap the valve
The mounting nut is removed, the old valve lifted out, and the new one set to the right height for the tank.
Set the level
After reconnecting and refilling, the float is adjusted so water stops at the fill line, below the top of the overflow tube.
Questions to ask before parts are replaced
- Which part is worn, and can you show me how you know?
- Is the flush valve seat in good condition?
- Are you using parts made for this toilet or universal parts?
- Is the shutoff valve working well enough to rely on?
- What is the written price for parts and labor?
Common questions
Should the fill valve and flapper be replaced together?
Not necessarily. Replace the one that has failed, though when both are old and worn, some homeowners choose to do both at once.
How do I know what size flapper I need?
Measure the flush valve opening or check the toilet's brand and model, often printed inside the tank behind the water line.
Why does my new flapper still leak?
The flush valve seat may be scaled or pitted, or the chain may be too short. If the seat is damaged, the flush valve may need replacing.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.