How To Fix That Hissing Sound From Your Toilet

A hissing toilet isn't an uncommon issue and can be caused by a number of factors. Fortunately, it's usually a simple fix that shouldn't require a plumber. The quiet sound of trickling water is generally caused by a faulty fill valve, the part of the tank that helps control the water flow. You might be wondering if it's a big deal if you just let the water outpour. According to the EPA, modern-day toilets use 1.28 gallons of water per flush. (Federal law states that your porcelain throne does not exceed the 1.68 water per flush threshold.) If a regular toilet flushes around 19 to 24 gallons of water per day, that averages out to around 7,500 gallons per year. 

If your toilet has an issue, like it's hissing and constantly running, a small leak can mean losing up to 22 gallons of water per day, as noted by This is not the time to waste water or turn a blind eye toward small, easily repairable leaks. Not only is it wasteful, but it's sucking dollars out of your bank account. Of course, you can always shut off the water to your toilet whenever you're done doing your business. But that also means you have to remember to turn it on again. Do you want to do that every single time someone uses the loo? We didn't think so, either.

What's going on under the lid

If your toilet sounds like an angry snake, the first thing to do is remove the lid from the back. Chances are, there is no snake; if there is, call animal control! Upon inspection, take a look at the major components of your toilet: the float (that big balloon-looking thing), the flush chain (attached to the float), and the flap valve (bottom of the tank). You'll need to replace the chain if it is broken or too long or short. If the valve isn't fitting or dirty, you'll need to clean it or replace it with a properly fitting one. Next, flush your toilet. Does anything look like it's not quite right? If so, it's probably time to replace a part or two.

Take note of the fill valve — the long tube on the handle side of the john. If it's leaking water down the side or continues to flow into the tank even after it's full, congratulations! You've discovered the culprit. Your next step will be adjusting the fill valve. Locate the screw on top of the valve and slowly turn it clockwise until you no longer hear the hissing. If this solves the problem, put the lid back on the pot and pat yourself for a job well done. If not, don't worry; there's one more thing to try.

Replacing the fill valve

If your toilet continues to leak, you'll probably have to replace the entire piece. While it seems like it might be difficult, it's not. Just remember that the first and most important thing you must do is shut off the water supply to the toilet and then flush it to drain the tank. Disconnect the water supply line from the bottom of the tank and remove the old fill valve. Install the new valve according to the manufacturer's instructions, then reconnect the water supply line. Hold your breath as you turn the water supply back on. Hopefully, you'll be greeted with the sound of nothing. If it's still making noises or seems to have gotten worse, turn the water back off and call a professional. 

Calling a plumber is always a good idea if, at any time, you don't feel comfortable tinkering in your toilet. There's no shame in asking for help, and that's what they're there for.