toilet tank not filling but water running
Kristina Davis

It can be heartbreaking and tiring to realize your toilet tank is not filling, but water running.

Is there any valid reason why the tank wouldn’t fill when water is actually running as it should?

This is an issue since when the tank doesn’t fill, then the toilet can’t flush. 

This issue could include one or a few unique parts. Continue reading this article to discover why tank is running but not filling.

If your toilet tank is running but not filling, then it might be because of several reasons. The problem amongst many others might be that of a faulty float or that the supply lines are not clogged.

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Toilet Tank Not Filling but Water Running?

why is tank not filling

Below are the various parts of the tank that might glitch and lead to this issue, and also the various ways you can fix this issue.

The Float

One of the things to do when the toilet tank is running but not filling is to check the float.

Most importantly, the float’s role is to hold the tank back from spilling over when it gets full with water immediately after you flush. 

If the float is not working properly, the problem is typically the setting is too low, and then the tank can’t top up totally.

You can address this by changing the position float so that the level of the water in the tank is sufficiently high after flushing. 

If at all you’re experiencing issues changing the position of the float, it’s good you replace it with another one.

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replace toilet float

Below are the steps to take when replacing your toilet float.

The Most Effective Method to Replace Your Toilet Float

When tank is not filling but water is running, you can replace the float.

The following are step-by-step instructions on how to change your toilet float.

Switch Off The Supply Of Water

The initial step is to make sure the supply of water is switched off. There is a valve underneath the toilet.

Rotate it counterclockwise to switch it off adequately.

Deplete The Toilet Tank

Hold the handle and push it down till the water is drained.

Assuming that you’ve switched the supply off appropriately, the tank won’t fill up even after flushing it.

deplete the toilet tank

You might in any case have a modest quantity of water remaining in the actual lower part of the toilet tank. 

Tip: You can drain it by absorbing it with towels.
Eliminate The Float

Assuming the toilet is old, with the ball kind of floating, it’s exceptionally simple to eliminate.

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You simply unscrew it from where it’s joined to.

If it’s a fresher toilet furnished with a fundamental (plastic chamber) float, the expulsion cycle is somewhat more confounded.

You should unscrew that nut that holds the valve set up at the lower part of your toilet tank. 

Note: You'll likewise have to detach the little hoses in the tank out from your toilet float.
attach new float
Attach The New One

The old floats are not difficult to screw back to the floating bar. The fresher, indispensable style drifts essentially should be connected to the supply line.

This can be fixed via the hole, at the base of the water tank. 

Reconnect it to the little water hoses at the highest point of the water tank. That is all there is to it!

However, this sort of work isn’t ideal for everybody. 

Note: You can always seek assistance from a professional when it’s too much for you to handle.

Check The Toilet Water Pressure

check water pressure

Aside from a defective fill valve, another likely explanation is the pressure of the water to your toilet is excessively low.

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This is brought about by clogged up or leaking pipes.

Deciding whether the low water pressure is just influencing your toilet or other pipes in your home is the principal thing to do.

If it is just the toilet, you can check if it’s blocked. Simply bring it out, then blow air into it. If the problem persists, invite an expert to fix it.

The Water Supply Line

Once in a while, the supply line can develop clogs, making the toilet fill gradually.

Turn off the switch of the supply valve at the wall, normally situated underneath the tank to cut the water supply. 

check water supply line

Once the supply is cut, disengage the water supply line at the toilet and direct it to a can. Then, walk out.

If the water turns out in trickles or it doesn’t at all, it’s most likely that the supply has been clogged.

If there’s no obstruction, then there could be a hole in some places along the supply line or in the actual lines.

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In this case, seek the help of a professional.

The Flapper

It’s the rubber component at the lower part of the tank which is pulled vertically during flushing.

It permits water to get into the tank, so you can flush.

Then the toilet flapper goes back into its normal position, sealing the tank and permitting the water to refill.

rubber toilet flapper

Peradventure the flapper can’t make a decent seal, your toilet tank won’t fill regardless of whether the water rushes consistently.

Then again, on the off chance that your flapper isn’t working, the toilet might flush two times. 

It can occur if the toilet flapper is distorted or old or because the entire component isn’t working. 

Tip: At the point when this occurs, it implies it's the ideal opportunity for another flapper.

The Most Effective Method to Change a  Flapper

methods to change flapper
  • Switch off the supply of water to the tank.
  • Eliminate the water in the tank by flushing the toilet.
  • Unfasten the chain away from the toilet’s handle arm.
  • Eliminate the pegs that join the flapper from the overflow tube
  • Clean the region where the new one will occupy.
  • Introduce the new one and install the pegs to the tube.
  • Connect the handle arm and lift chain.
  • Switch on the supply of water to the tank.
  • Ensure the tank is getting filled
  • Keep the tank cover back
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The Trip Assembly

The handle you use to flush your toilet is referred to as the trip lever. It is the part that is inside the tank, associated with the handle outside.

Assuming the trip components get twisted or broken, the toilet won’t flush as expected.

This implies the tank likewise won’t fill as expected after flushing. 

assembling toilet trip valve

Normally, the best thing to do with a wrecked trip lever is to supplant it with another one yourself.

Or, on the other hand, you can recruit a handyman to finish the work for you.

The Fill Valve

It is situated inside the tank on the left side. It redirects water into the tank after you have flushed.

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At the point when the fill valve isn’t working, it might be blocked or it may very well be excessively old. 

Fill valves additionally break once in a while. With them all, the speediest and least demanding fix is to replace the valve with another one. 

An accomplished DIY can deal with this without calling in a professional.

Be that as it may, assuming you endeavor to fix this issue but then realize that the toilet is spilling over at the tank, stop there and then and call in a handyman.

fix toilet fill valve

Step By Step Instructions To Fix A Toilet Fill Valve

  1. Switch off the water supply to the toilet.
  2. Flush the toilet.
  3. With one hand, hold the shaft of the fill valve at the base and utilize the other hand to give the fill valve cap a 1/8 go counterclockwise to eliminate it.
  4. Investigate the openings on the valve seat for flotsam and jetsam.
  5. Hold a vacant cup over the fill valve to stay away from water sprinkling and completely switch on the supply of water to the tank. 
  6. The water strain ought to compel the trash out but at the point when the valve is unblocked, place the fill valve cap back on.
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If you have an old/broken down fill valve, you ought to supplant it.

Fill valves are cheap, and in some cases, it seems OK to supplant than fix.


When the tank isn’t filling but running, it may be difficult to figure out the part of the toilet creating problems.

This article has explained the different parts of the toilet that might have a fault and how to fix them. 

So in the event, you are still wondering, is toilet tank not filling but water running? We hope the fix guide in this article was helpful. 

However, if the fix is too much for you, it’s best to contact a professional to analyze and fix the situation as they are more knowledgeable and also save time.