A toilet flush valve controls the flow of water from the tank into the toilet bowl. It is made of a valve body, a flapper, and a chain. When you flush, the chain lifts the flapper and water flows from the tank into the bowl and carries away waste. When the flapper closes it seals off the valve seat at the bottom of the tank so that the tank can refill with water for the next flush.
When this plastic valve cracks, wears out, or accumulates mineral deposits from hard water, water can leak through and cause a running toilet. Replacing this faulty valve promptly can save water and reduce utility bills and doing it yourself is easy enough and will save on professional labor costs.
Signs That the Flush Valve Needs to Be Replaced
- Constant Running Water: A leak forces the toilet tank to constantly replenish the loss.
- Incomplete Flushing: Weak flushes mean that the valve might not be opening fully or closing properly.
- Hissing or Gurgling Sounds: Unusual noises, such as hissing or gurgling, can be a sign of water escaping through a faulty flush valve.
- Higher Water Bills: A sudden jump in your water bill without any other explanation might mean there is a toilet leak.
- Frequent Need to Adjust the Flapper Chain: These things will disconnect as they wear out.
- Water on the Floor: If you notice clean water (no sewage smell) pooling around the base of the toilet, it indicates a leak between the tank and the bowl.
How to Confirm the Flush Valve Needs Replacement
- Dye Test: Add a few drops of food coloring to the tank water and wait for 15-30 minutes without flushing. If colored water appears in the toilet bowl, you have a leak.
- Visual Inspection: Remove the tank lid and inspect the flapper and flush valve assembly for visible signs of damage or wear.
- Check for Tight Seal: Push down on the flapper mechanism. If the water stops running, this indicates a flapper is not sealing properly. Mineral deposits may prevent a seal between the flapper and the valve seat. It could also indicate a faulty flapper that needs replacing.
How to Replace a Faulty Flush Valve
1. Turn off the water supply. The shut-off valve is at the base of the toilet. Turn it clockwise.
2. Empty the tank. To do this, flush to the toilet.
3. Remove the Tank Lid and Flush Handle:
- Lift the tank lid off and set it aside in a safe place.
- Use a sponge or towel to soak up any water in the tank.
- Disconnect the flapper chain or lever from the flush handle. Remove the handle from the outside of the tank.
4. Disconnect Water Supply Tube:
- Put a floor covering around the base and a bucket beneath the connection to catch any remaining water.
- Use an adjustable wrench to loosen and disconnect the water supply tube from the bottom of the tank.
5. Remove the Tank from the Toilet Bowl:
- At the bottom of the tank, you'll see the toilet bolts that secure the tank to the bowl.
- Remove the toilet bolt caps. Use an adjustable wrench to loosen and remove the nuts from the bolts. You may need a screwdriver to hold the bolt heads inside the tank while you turn the nuts.
- Note how the metal and rubber washers are arranged so that you put them back correctly later (rubber against porcelain, metal against the nut).
- Lift the tank off of the bowl (it's heavy) and lay it on a towel to prevent damage.
6. Remove the Old Flush Valve:
- Remove the rubber or spongey spud gasket from under the tank. If it looks deteriorated this is a good time to replace it.
- Unscrew the plastic lock nut from the bottom of the tank with a pair of pliers whilst holding the overflow tube inside to prevent it from spinning.
7. Install the New Flush Valve:
- Place the rubber gasket or washer provided with the flush valve replacement kit onto the threaded portion of the valve.
- Insert the valve into the opening at the bottom of the tank. The rubber washer should create a watertight seal.
- Hand-tighten the locknut onto the threaded portion of the valve.
- Use a wrench or pliers to further tighten the nut, being careful not to over-tighten and damage the valve or tank.
- Replace the rubber spud gasket.
8. Reattach the Tank to the Bowl:
- Carefully lift the tank back onto the bowl unit.
- Look into the empty tank and line up the holes. Place a metal washer and then a rubber washer onto the bolts and insert through the ceramic hole with the rubber washer sitting flush with the porcelain. Remember, the hardware will be in reverse order on the underside of the tank.
- Reattach the nuts to the bolts and tighten them evenly. Avoid over-tightening, as this can crack the porcelain.
- Replace the bolt covers.
9. Reconnect the Water Supply Line:
- Attach the water supply line to the bottom of the tank by threading it onto the connector on the new flush valve.
- Use an adjustable wrench to tighten.
10. Test for Leaks:
- Turn the shutoff valve back on.
- Allow the tank to fill completely. The tank water level is about 1 inch below the top of the overflow pipe.
11. Reassemble the toilet. Reattach the flush handle and chain to the new valve.
12. Test the flush. Test the toilet flush several times for strength.
Other Reasons the Toilet May be Running
- Toilet Fill Valve: Found on the tank's left side, this sets the correct water level. If set too low, the flush will be weak. Set too high and water will constantly flow into the overflow tube.
- Float: Typically a rubber tank ball or cup, it regulates the water level. Damage can lead to tank overflow and continuous water replenishment.
- Flush Handle: A broken or stuck handle keeps the flush mechanism engaged, resulting in continuous water flow.
