How To Repair a Noisy Toilet

A noisy toilet can be more than an annoyance—it can disrupt your sleep and potentially signal underlying plumbing issues. Fortunately, you can resolve many toilet noises with some basic DIY skills and a few simple tools. In the video above, This Old House plumbing and heating expert Richard Trethewey shows how to diagnose and fix a persistently noisy toilet by replacing the flush valve.

Common Causes of Toilet Noise

If your toilet makes unfamiliar sounds, you might have problems with your fill valve, flush valve, or other loose parts.

Faulty Fill Valve

The fill valve controls the water flow into the tank after flushing. If it’s malfunctioning, it can cause a variety of noises, including the following:

• Hissing or whistling sounds
• Loud banging when the tank refills
• Whining after a flush

Worn Flush Valve

A worn or damaged flush valve can lead to water leaking from the tank into the bowl, potentially causing issues like the following:

• Constant running water
• Gurgling sounds
• Phantom flushes

Loose Parts

If you notice any of the following sounds, there may be loose components within the tank:

• Clanking noises from the flush lever
• Rattling sounds when flushing
• Vibrations during tank refill

Diagnosing the Problem With Your Toilet

To repair your noisy toilet, you first need to identify the source of the problem. In the video above, Trethewey helps a homeowner diagnose the issue with her toilet, which has been making noise day and night. He follows these steps:

• Check the tank components: Remove the tank lid and observe the internal parts while flushing. Look for any visible signs of wear, damage, or misalignment.
• Listen carefully: Pay attention to when and how the noise occurs. Is it constant or intermittent? Does it happen only when flushing or at random times?
• Perform a dye test: Add a few drops of food coloring to the tank water. If the color appears in the bowl without flushing, you likely have a leaky flush valve.

Once you’ve determined whether your flush valve is the culprit, you can proceed with the repair process we outline below.

Tools and Materials Needed to Fix a Toilet

Before starting your toilet repair, gather the following tools and materials:

• Adjustable wrench
• Bucket or towels (for potential spills)
• Large sponge
• New valve assembly (if needed)
• Pliers
• Slotted screwdriver

Step-by-Step Flush Valve Repair Process

Follow these steps to replace a faulty flush valve and silence your noisy toilet:

1. Close the shutoff valve behind the toilet to stop the flow of water.
2. Remove the lid from the toilet tank.
3. Flush the toilet and hold down the flush lever to drain as much water from the tank as possible.
4. Use a large sponge or cotton cloth to sop up the remaining water from inside the tank.
5. Disconnect the water supply line from the underside of the toilet tank.
6. Use a slotted screwdriver and open-end wrench to remove the two bolts that hold the toilet tank to the bowl. Trethewey warns that there could be some water in this section, so be careful when removing the bolts.
7. Lift the tank off the bowl and use pliers to remove the large nut on the underside of the tank.
8. Remove the old flush valve from the tank.
9. Install a new flush valve to the tank and securely tighten the mounting nut with pliers.
10. Attach two new brass bolts to the tank.
11. Place the rubber spud gasket onto the bottom of the flush valve (in the video, the new flush valve comes with a spud gasket). Set the tank onto the toilet bowl.
12. Put washers and hex nuts onto the brass bolts, then alternately tighten the nuts to secure the tank to the bowl. Make sure the tank is level. Be careful not to overtighten the nuts or you’ll crack the toilet.
13. Reconnect the water supply line to the underside of the tank. Again, be careful not to overtighten.
14. Adjust the flapper chain to the correct length before turning on the water. As Trethewey explains, you “want to be sure that the tank lever’s action lifts that flapper right away and makes it flush properly.”
15. Turn the water back on and flush the toilet to ensure it’s operating properly and quietly. Adjust the flapper and overflow tube if necessary.

Adjusting the New Flush Valve

Modern flush valves often come with additional features that allow for fine-tuning, such as the following:

• Flush volume control: Some valves have adjustable settings to control the amount of water used per flush without sacrificing performance.
• Overflow tube height: An adjustable overflow tube keeps the water from rising too high in the tank, preventing overflow.
• Water level adjustment: You can adjust the water level in the tank using the fill valve. This helps optimize flushing performance and water conservation.

Choosing the Right Flush Valve for Your Toilet

There are several types of flush valves available, each designed to meet different needs.

Dual Flush Valves

Dual flush valves offer two flush options: a low-volume flush for liquids and a full-volume flush for solids. Many environmentally conscious homeowners prefer this style.

Flapper Flush Valves

Flapper flush valves are the most common flush valve type. A flapper valve lifts a rubber flapper to release water from the tank into the bowl. This valve type is easy to install and widely compatible with many toilet models.

Tower-Style Flush Valves

Tower-style flush valves offer a vertical design with a gasket that raises and lowers to allow or stop water flow. They work faster than flapper valves and are often found in high-efficiency toilets.

Flush Valve Installation Tips

A properly installed flush valve can help reduce toilet noise and improve efficiency. Here are some tips to keep in mind:

• Check for leaks: After reinstalling the tank and turning the water back on, closely inspect all connections for leaks. Even a small leak can lead to further issues down the line.
• Ensure a tight seal: Make sure all gaskets are properly sealed. A tight seal will prevent leaks and help the flush valve operate correctly.
• Follow instructions: Always follow the manufacturer’s installation instructions.

Preventing Future Toilet Noise

Once you’ve resolved your toilet noise problem, take the following preventive measures to keep your toilet running quietly in the future:

• Avoid flushing nonbiodegradable items that can clog the system.
• Perform regular maintenance checks.
• Replace worn parts promptly.
• Use toilet-safe cleaning products to prevent damage to internal components.