How to Fix a Broken Toilet

Gear-obsessed editors choose every product we review. We may earn commission if you buy from a link. Why Trust Us?

Fill valve kits are designed with DIY installers and handy people in mind.

It’s annoying. One moment a toilet flushes reliably. The next, it doesn’t. In most cases, the fix is fast and simple, requiring a few minutes of work and a trip to the hardware store or home center. But let’s take a worst-case example. Suppose the toilet’s fill valve is shot. Again, it’s not a big deal. Fill valve kits are designed with DIY installers and handy people in mind. Honestly, there’s not much to installing one.

The first step is to lift the toilet tank lid and have a look inside.

Step 1: Investigate the Flush Lever and Flapper valve

The two most common sources of toilet malfunction are the flush lever and the flapper valve to which it is connected. The flush lever is mounted through the side of the toilet tank, and it’s attached to a lever and chain which in turn attaches to a flexible rubber flap covering the hole in the bottom of the toilet tank. Push down on that lever and you pull the chain tight and in the process lift the flapper, causing water to flow out of the tank into the bowl.

To investigate proper operation of the lever and flapper valve, pull off the toilet tank lid and push down on the flush lever. You should see a full swing of the lever, the slack come out of the chain, and a smoothly lifting rubber flapper valve. If this doesn’t happen, it could be that the flush handle is broken, there is too much slack in the chain, or that the flapper is all or partially disconnected or simply worn out.

There are several possible solutions to sloppy lever, chain, and flush valve problems.

Step 2: Investigate the Fill Valve

Many toilets today use a plastic fill valve assembly manufactured by Fluidmaster. These all-plastic valves are extremely durable. It’s not unusual to have them last a decade or more, even with countless hours of being submerged under water. As good as they are, though, they can still wear out

Flush the toilet and take a good look at the fill valve. If its float doesn’t move up and down on its tower or its water flow is erratic, replace it. In the worst case, when you lift the toilet tank lid, you may find an out-dated flush valve consisting of rusty and water-logged metal parts. Replace this with a modern Fluidmaster.

Install a new fill valve. But first watch this video in which Popular Mechanics contributor Mark Clement (a contractor and proprietor of myfixituplife.com) installs a new Fluidmaster fill valve. He uses nothing more than a pair of pliers. It’s really pretty easy. Even a novice do-it-yourselfer can handle this job.

Let’s just say the fill valve, flapper, and handle are in good working order but the toilet’s flush is still not clearing the bowl.

The problem may be calcified rim jets. These are the small concealed holes along the rim of the bowl that send water down from the rim into the bowl. Over time, they may become clogged or partially clogged by mineral deposits.

Inspect the rim with a mirror and, if necessary, give the rim a thorough scrubbing with a generous amount of acidic mineral-removing cleaner, such as CLR. Pour some of this cleaner into the bowl and use a toilet brush to slosh it around the bowl and scrub up under the rim. Give the cleaner 10 or 15 minutes to work and inspect again. Re-apply if necessary and keep scrubbing until the jets are clear.

Roy Berendsohn has worked for more than 25 years at Popular Mechanics, where he has written on carpentry, masonry, painting, plumbing, electrical, woodworking, blacksmithing, welding, lawn care, chainsaw use, and outdoor power equipment. When he’s not working on his own house, he volunteers with Sovereign Grace Church doing home repair for families in rural, suburban and urban locations throughout central and southern New Jersey.

Make Your Own Smoker Out of a 55-Gallon Barrel

These Are the 3 Most Expensive Home Reno Projects

Clean Your Bath Fan

The Right Way to Prune a Tree

Are You Sure You Know How to Use a Screwdriver?

How Do Air Purifiers Work, Exactly?

Chopping Metal is Fun With a Cold Chisel

How to Kill Those Pesky Mosquitoes in Your Yard

Watch Klein Tools Forge Its World-Famous Pliers

This Is the Best Time to Water Your Grass

6 Tips for Installing Your New In-Ground Pool

We Built a Cool Mid-Century Influenced Desk