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Tips for diagnosing and fixing a toilet that doesn’t fill after you flush
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If your toilet tank isn’t filling with water after flushing, you may not see any water in the tank at all, which can prevent it from flushing. Or if there is some water in the tank, it may not register that it's full, causing the toilet to run continuously. Either way, we’re here to help. We'll break down the reasons your toilet tank isn’t filling, including how to figure out what’s causing the problem, how you can fix it, and how much the repair will cost.

Why isn’t my toilet tank filling with water after I flush?

If your toilet tank isn't filling with water after you flush, you might have a worn-out flapper, a damaged fill valve, a clogged or displaced fill tube, or a closed water supply valve. To fix it, replace damaged parts or adjust the water level or the length of the chain.

Section 1 of 8:

The flapper is worn out.

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  1. The toilet flapper seals the bottom of your toilet tank—when you flush, the toilet handle lifts the chain, which opens the flapper and lets water out of the tank. But rubber flappers can warp or wear out over time, and if it doesn’t seal properly, the toilet tank won’t fill up after you flush. [1]
    • How to diagnose : If you haven't replaced the toilet flapper in 4-5 years, it's probably worn out. [2]
    • How to fix it : To replace the flapper , turn off the water to the toilet, then unclip the old flapper from the chain and pull it off of the pegs on the overflow tube. Slip the new flapper onto the pegs on the overflow tube, then reconnect the chain. [3]
      • Toilet flappers come in 2 in (5.1 cm) and 3 in (7.6 cm) diameters. Bring the old flapper with you to the hardware store so you’ll know which size to buy. [4]
    • How much does it cost? A new toilet flapper usually costs between $5 and $15.
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Section 2 of 8:

The flapper chain is the wrong length.

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  1. A flapper chain should have 1 2  in (1.3 cm) of slack. If the chain attached to your toilet flapper is too short, the flapper might not close all the way, which can prevent your toilet tank from filling with water. If it’s too long, the chain can get tangled or twisted, which can also cause the flapper to stay open. [5]
    • How to diagnose : If the chain has more or less than 1 2  in (1.3 cm) of slack in it, it’s probably the wrong length.
    • How to fix it : Move the clip up a few chain links if the toilet chain is too short. Move the clip down a few chain links if it’s too long. If the chain is damaged, unclip it from the flapper and handle lever, then clip the new one into place.
    • How much does it cost? Adjusting the chain is free. But even if you need to replace the chain, a new one only costs between $5 and $10.
Section 3 of 8:

The refill tube is out of place or damaged.

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  1. The refill tube is a small flexible hose that runs from the fill valve to the overflow tube. This tube is actually responsible for filling the toilet bowl. In some cases, it can move out of place, which can cause the tank to overfill, so it sounds like it’s running constantly. The tube can also become cracked or clogged, which can prevent the tank from filling up. [6]
    • How to diagnose : Remove the lid from the back of the tank and look at the refill tube—if it’s not in the overflow tube, that’s probably your issue. If it is in the overflow pipe, check the refill tube for cracks or other damage. If it looks fine, flush the toilet to see if water comes out of the refill tube.
    • How to fix it : If the refill tube is out of place, insert it into the hose. You may need to add a clip to secure it. If the tube is cracked or clogged, detach it from the refill valve, then push a new refill tube onto the port on the refill valve and place the end with the clip into the overflow tube. Attach the clip to the tube.
    • How much does it cost? You can purchase a new refill tube and clip for around $10.
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Section 4 of 8:

The fill valve is clogged or damaged.

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  1. If your fill valve is clogged, worn out, or broken, water won’t be able to get into the tank after you flush. Fill valves usually need to be replaced about every 5 years or so. [7]
    • How to diagnose : If your toilet tank is noisy, constantly runs, or takes a long time to fill up, the fill valve could be to blame.
    • How to fix it : To replace a toilet fill valve , turn off the water and drain the toilet, then disconnect the water supply and lock nut from the bottom of the tank and pull out the old fill valve. Adjust the height of the new fill valve so it’s about 1 in (2.5 cm) above the overflow tube, then put the fill valve in place and reattach the hose, lock nut, and water line.
    • How much does it cost? A new toilet fill valve costs $10–$20.
Section 5 of 8:

The inlet holes are clogged.

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  1. The inlet holes, or rim jets, around the rim of the toilet bowl can become clogged and prevent water from entering the bowl from the tank. Over time, debris and sediment can build up around the holes, which can block water from entering the bowl. [8]
    • How to diagnose : Do a visual inspection of the rim around the inside of the toilet tank and look for sediment clogging the holes.
    • How to fix it : Use a toilet brush to clean the rim of the toilet. If necessary, use an awl or a piece of wire to unclog the holes, but be careful not to crack the toilet.
    • How much does it cost? Free
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Section 6 of 8:

The water level is incorrect.

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  1. Ideally, the water level in your toilet tank should stop about 1 in (2.5 cm) from the top of the overflow tube, which is the pipe next to the flapper and chain. If the water level in your tank too high, water will constantly pour into the overflow tube. This can make it sound like the toilet tank is never full. [9]
    • How to diagnose : Wait at least 30 seconds after you flush the toilet, then take the lid off of the toilet tank and observe the water level. If it’s less than 1 in (2.5 cm) from the top of the overflow pipe, it’s probably causing your toilet to run.
    • How to fix it : Adjust the fill valve by turning the adjustment screw or lowering the clip to drop the float. This will lower the water level, which should stop the toilet from running.
    • How much does it cost? Free
Section 7 of 8:

The water supply valve is closed.

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  1. The water supply valve connects your water line to the toilet. If that valve isn’t open all the way, the toilet tank will refill slowly after you flush it. [10]
    • How to diagnose : If you’ve recently turned off the water supply to your toilet , you may not have opened it all the way again.
    • How to fix it : Find the water supply valve—it's usually located on the wall behind the toilet, close to the tank. Turn the valve counterclockwise to be sure it’s completely open.
    • How much does it cost? Free
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Section 8 of 8:

The tank is cracked or leaking.

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  1. A crack or a leak in your toilet tank can prevent it from holding water. This might cause the toilet to run continuously, or you might notice the level in the water tank isn’t as high as it usually is.
    • How to diagnose : Inspect your toilet for any cracks, or check around the base of the toilet for drips or leaks.
    • How to fix it : You’ll probably need to replace the toilet . You can either do this yourself or call a professional plumber.
    • How much does it cost? Having your toilet replaced by a professional can cost between $350 and $800. [11]

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      • If you’ve tried to diagnose and fix the problem yourself, it’s probably time to bring in a professional plumber. You might also want to consult a plumber if your toilet is cracked and needs to be replaced or if you aren’t comfortable working on a toilet. [12]
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