When Your Toilet Fills Slowly It’s Not For Energy Conserving Purposes

Written by Toilets

Modern low-flow toilets are a great way to conserve water in an effort to lower your utility bills. When the toilet fills slowly your first inclination may be that somebody replaced it with an energy saving model when you weren’t looking. That would be a great surprise gift, but the more likely result is that components have become damaged to the extent that your tank is not filling properly.


One of the first questions that comes to mind is, “what’s so bad about a slow filling toilet?” If the same amount of water is being put into the tank it shouldn’t matter what pace it goes in there, right?

For one, a toilet tank filling slowly is annoying. Simply not having to listen to a constant supply of water going into the toilet should be incentive enough to get the problem fixed. Another potential problem is that you walk out of the room thinking the long-running water is just another example of when the toilet fills slowly. However there could be a clog which could cause the tank not only to fill slowly, but also to fill overtop the bowl – something you might have caught under the normal flow rate. Finally, a slow filling toilet could lead to other leaks and problems down the line.

What Causes the Slow Filling Toilet?

Luckily the fix for a slow filling toilet is generally pretty easy. The problem usually originates from a water supply from your bathroom wall that has been compromised either by a kink, from a debris blockage, or from a valve being bumped or turned off. You should first make sure the valve is opened up as that is the quickest and easiest fix.

If the toilet fills slowly even after checking the valve, the cause could be debris in the line. The next step should be to remove the valve from the port where it enters the toilet (after turning off the water supply). Once the valve is detached you can turn the water back on so that the force of the water, along with no restrictions from the toilet, pushes out the debris. Placing a small wire hanger into the valve tube can also help to joggle the debris.

If there is plenty of water flow however, it means the toilet fills slowly because of an issue inside the tank. A few areas to check include:

  • Floater is waterlogged and thus not allowing the water to fill up as designed.
  • Fill line inside the tank is clogged with debris and thus not allowing normal water flow.
  • Rotted flapper or valve seals are allowing water to enter into toilet bowl instead of staying in the tank.
  • Gaskets around bolts have ripped or deteriorated dripping water onto the floor.
  • A crack in the tank or toilet bowl is leaking water.

It’s because of these reasons that the problem of a toilet fills slowly should not be taken lightly. Replace as many of these components as necessary to restore proper working order and to stave off any further damage.

Kevin L. Sharp

Kevin L. Sharp

He began his career in plumbing at the age of 14 while still in high school. Kevin Sharp has a bachelor's degree in journalism from Illinois State University.
Kevin L. Sharp

Last modified: September 12, 2017

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