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There’s Noise in My Pipes When Flushing the Toilet: 4 Reasons

toilet valve

Noises from pipes after flushing are distressing and, unfortunately, embarrassing. What could be the problem? In this article, you’ll learn about the unfamiliar noises you hear in pipes when flushing a toilet, their causes, and how to fix them.

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The 4 Reasons Why There’s Noise in Your Pipes When Flushing the Toilet

1. Vibrating/Foghorn Sound in Plumbing Pipes

Toilet shape_Shutterstock_Happy_Nati
Image Credit: Happy_Nati, Shutterstock

When you flush your toilet and pipes start emitting a vibrating sound for about 30 to 40 seconds, there is a high chance the fill valve is defective. The fill valve refills water in the toilet tank and cuts off the water supply when water reaches a certain mark using a diaphragm.

This diaphragm is a rubber-like material that prevents water from filling up the tank past the watermark. With time, the diaphragm stiffens up. This makes it “rattle around” instead of forming a tight seal as the water fills up, emitting vibration noises. They are very common in older toilets.

To make sure the issue is the fill valve, remove the lid of the toilet tank and flush. As soon as the noises start, lift the flat ball upwards gently to stop the water flow. If the sound stops, you need to repair your fill valve. Though you can repair a fill valve, it is best to install a new one.

If the damage is severe, you would need to replace the entire ballcock valve. Ready for a DIY challenge? Replace the valve yourself by unscrewing the hose from the base of the tank, followed by the plastic lock nut and removing the supply valve. Adjust the height of the new gasket and slide it into place. Tighten the plastic nut and connect it back to the hose pipe.

2. Hammering Sound in Plumbing Pipes

Are you hearing hammering sounds whenever you flush your toilet? If you do, your toilet is suffering from a “water hammer.” This phenomenon occurs when the valves used to control water flow in a piping system are under abnormal pressure.

When a pressure surge or high-pressure shock wave is occurring in the piping system forcing the water to change direction or stop abruptly, it causes the sound of hammering, banging, or knocking sounds.

Ignoring water hammers can cause serious damage. If left unattended for a long time, they can cause significant damage to the pump and flow system of the toilet, cause leaks and ruptured pipes, and damage external property.

To resolve water hammering in your pipes, hire a professional plumber to replace the hammer arrestor.

For older toilets, it would be prudent to change the entire system since water hammering affects them disproportionately.

3. Running Water Noise When Flushing

toilet flushing
Image Credit: Am.p, Shutterstock

When you flush and hear noises, it means the toilet tank is filling up. It may also be that there is a leak in the tank. However, if you hear noises when there is no flushing, it could be the valve in the tank is loose and is allowing water to flow into the toilet bowl.

It could also be that the flapper chain on the toilet handle is too tight, preventing the valve from shutting all the way, or the float is too high, causing the water to keep running. To fix this, remove the lid on the toilet tank and examine the float’s position.

If it is higher, turn the float adjustment screw clockwise, which should solve the issue. If it doesn’t work out, look at the flapper chain and adjust it.

Remove the toilet handle’s clip and increase or decrease the length until the issue is resolved. If you’re still not having luck, call a plumber to inspect. A plumber will unscrew the handle and take a keen look into its working mechanism. You may need to replace a few parts.

4. Gurgling Noise When Flushing

A gurgling noise when flushing means a pipe or your toilet is clogged. The clog creates negative air pressure, and instead of air going through the pipes, the air is pushed back, causing the gurgling noise. In some instances, you’ll see the toilet water bubble.

Other than a toilet/pipe being clogged, a gurgling noise can be caused when the vent stack is blocked or there is a mainline or sewer line problem. To fix a gurgling toilet, give your toilet ten to fifteen plunges. If the clog is near the surface, it should dislodge. If not, try an auger or snake and work through the clog.

To prevent your toilet from clogging, only flush waste, water, and toilet paper. Avoid flushing feminine hygiene products, paper towels, medication, baby wipes, cat litter, cigarette butts, cotton balls, and swabs. Set a garbage can in the toilet to avoid the temptation of throwing things in the toilet.

If you’ve ruled out a clogged toilet, next investigate the mainline. Call your neighbors and ask them if they are having a gurgling toilet. If they are, the problem would likely be the main sewer line. Call your city sewer authority to come and inspect. If there is a problem, they will repair the sewer line at their cost.

When you’ve ruled out a clogged toilet or a sewer line blockage, next check the vent stack; the vent stack is a vertical pipe leading to the roof. It regulates plumbing air pressure and releases exhaust gasses.

It is an open channel; not even water should flow through it. When there is negative pressure in it, the toilet will start gurgling, and there will be a smelly sewer odor in your home. The main causes of vent blockage are fallen leaves, animal nests, rodents’ habitats, or a small carcass.

To fix this, go up your roof and take a peek. If there is any clog in the vent, clear it out. For safety reasons, find a professional to do it.

house divider Bottom Line

Having noises come out of toilet pipes when flushing is disconcerting. As mentioned at the top, it can also be embarrassing and costly. Use the above list to rule out what may be causing the noise in your toilet and fix it. If you’re unable to, seek the services of a professional plumber.

Featured Image Credit: _R Dorosh, Shutterstock


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