The flush valve is the part inside your tank that releases water into the bowl when you flush. When the handle or button is pressed, the valve opens (via a flapper or canister), letting tank water rush through the opening to create the flush. It then reseals to let the tank refill.

• Controls flush volume: The valve size (commonly 2" or 3") affects flow rate.
• Includes overflow protection: The overflow tube helps prevent overfilling.
• Works with the fill valve: After the flush, the fill valve refills the tank.

You’ll find universal and size-specific valves and complete repair kits available. Results may vary depending on your toilet design.

Common signs point to a worn seal, warped flapper, or a misadjusted setup.

• Constant running or refilling: You may hear periodic refills (“phantom flushes”).
• Water trickling into the bowl: Do a dye test—add food coloring to the tank; if color shows in the bowl without flushing, the valve isn’t sealing well.
• Weak or inconsistent flush: The valve may not be opening fully or sealing properly.
• Visible wear: Cracked overflow tube, brittle gasket, or mineral buildup on the seat.

Some symptoms overlap with fill valve issues, so a quick visual check and dye test can help narrow it down. If the flapper looks fine, consider a full flush valve kit.

For many two-piece toilets, it’s a moderate DIY project that can often be done with basic tools.

1. Prep: Turn off water, flush to drain the tank, and sponge out remaining water.
2. Access: Many installs require removing the tank to swap the valve body and gasket.
3. Install: Set the new valve height, position the gasket, and reassemble without overtightening plastic parts.
4. Adjust: Set chain slack and water level, then test for leaks.

Time and difficulty vary by toilet style (one-piece or dual-flush designs can differ). If you prefer a simpler fix, replacing just the flapper or seal is often quicker. Always follow the kit’s instructions.

First find where the leak is going, then address the likely cause.

• Leak into the bowl: Try a dye test. If color seeps into the bowl, clean the valve seat, adjust chain slack (not too tight or too loose), and replace a worn flapper or seal.
• Water level too high: Keep the water level below the overflow tube by adjusting the fill valve.
• External seep between tank and bowl: The tank-to-bowl gasket may need gentle retightening or replacement (included in many kits).

Turning off the water before repairs can help. These steps can reduce leaks, though results vary with toilet condition and installation.

Match the valve to the opening at the bottom of your tank.

• Measure the outlet: Remove the old flapper and measure across the hole—about 2" or 3".
• Visual cues: A 3" opening looks notably larger (often found on many newer, higher-efficiency toilets), while older models commonly use 2".
• Check style: Some dual-flush systems use tower/canister valves that are model-specific.
• Toilet type matters: One-piece and two-piece toilets may use different assemblies.

When in doubt, bring the old part or a photo of the tank internals. You’ll find universal and size-specific valves and complete kits, with pickup and delivery options for convenience.