You may have noticed your toilet tank is filling up more slowly. You may even need to flush more than once. It’s really inconvenient, but what can you do about it?

The most common cause is a clogged water fill valve, or the water supply is partially shut. First, turn your water supply off at the wall. Now remove the water fill valve cap and hold a cup upside-down over it while turning the water supply on again.

This procedure should clean debris out of the valve. Now make sure to reopen your water supply completely. This step should solve most of your slow filling problems.

Why Is My Toilet Filling Slowly?

There are several possible causes for this problem.
Float Ball Needs Adjusted: This is the most common cause of a slow filling tank. The float ball rests on top of the water and stops the water from flowing into the tank

Fill Valve Needs Adjusted: Fill valves allow water to flow from the supply lines into the tank. When the toilet is filling too slowly, you may need to adjust the fill valve.

Clogged Fill Valve: If material has built up inside the fill valve, water may fill slowly or not at all. You can solve this problem by cleaning the fill valve.

Flapper Problems: When the flapper is damaged, the toilet runs continuously. If this happens, the tank may not fill correctly. To solve this, replace the flapper.

Trip Assembly: The trip assembly consists of the parts that attach the flush handle to the toilet tank. If this is broken or poorly positioned, the toilet will not flush properly. If this appears to be true, you will simply need to entirely replace the assembly.

Water Shutoff Valve: The problem could be caused by the water shutoff valve being partially closed. Make sure this valve is completely open. Also, the water valve may be partially blocked; if it is, you need to clean it.

Pipes: The problem may not be the toilet but the pipes in your house. This could prevent enough water from reaching the toilet.

Check for Water Pressure

The first step should be to check if the problem is the toilet or the water pressure leading to your toilet. To do this, turn off the water at your wall. Place the water hose in a bucket; turn the water on and observe how quickly it fills.

If the water fills at an acceptable speed, the problem is your toilet. If it does not, then the problem is the water pressure leading to the toilet. Leaking pipes sometimes cause a loss of pressure leading to the bathroom, and you need to seal these or have a plumber seal them.

If your water pressure to the entire bathroom remains low, consider acquiring a toilet with an electric pump assist. Some tankless models offer these built in.

Why Does Toilet Tank Fills Slowly

Cleaning the Toilet Valve

Cleaning your toilet valve is an easy process that will often solve slow filling issues. To do this, follow these steps.

  1. Turn off the water supply. Simply twist the water supply valve from your wall clockwise to shut it off.
  2. Remove the valve cap. For many fill valves, simply hold the lever up and twist the cap counterclockwise. Gently pull the cap up and off.
  3. Clean the valve. To clean the valve, hold an inverted cup over the top of the fill valve. Now simultaneously hold the cup in place while turning the water supply on and off. Repeat a few times.
  4. Reassemble. Test to ensure that you solved the problem. If not, you may need to set the fill valve and float again.

Setting the Fill Valve & Float

You can set the valve and assembly to fill at different heights and at different rates. Follow these steps to set it properly.

Adjust the float. Move the float upward and flush your toilet. This should ensure your toilet opens the water flow until it fills to a greater height. This will also ensure it is fully opening.

Adjust the set screw. The top of your float valve should have a screw that controls at what point the water is shut off like the float. Adjust this until the water valve is properly opening and shutting when flushed.

Replace the Fill Valve

Sometimes, the fill valve may have a difficult repair problem, but replacing a fill valve is not hard. To replace your fill valve, follow these steps.

  1. Drain your toilet. Shut off the water supply at the wall and flush the toilet. Make sure you drain the water to the bottom. Now sop up the remainder with a rag or sponge.
  2. Remove the water supply hose. Untwist it by hand or with pliers. Twist it counterclockwise and pull off the bottom of the fill valve on the bottom of the tank.
  3. Remove the valve nut. Use pliers or an adjustable wrench and twist the valve nut counterclockwise to remove it.
  4. Remove the fill hose. This is held onto the overflow tube with a clip. Simply slip it off.
  5. Remove the fill valve. The fill valve should simply lift out now.
  6. Install the new fill valve. Reverse the disassembly to install the new valve. However, ensure the marking on the top of the valve is at least an inch above the overflow tube when setting the valve height.
  7. Set the float. Ensure the float allows the water to fill the tank, but not spill out the overflow tube.

Frequently Asked Questions 

How Much Water Should There Be in My Toilet Tank?

Once you adjust your toilet, so it is filling at an appropriate rate, you should make sure it holds the right amount of water. This may not seem important, but too much or too little water can result in problems.

Too much water in the tank could lead to the toilet overflowing or not flushing all the way. Whereas too little water could result in clogs. Therefore, it is a good idea to adjust the water level if it isn’t right.

Fortunately, you should have no trouble if you follow these instructions.

  1. Take the lid off of the tank. Then, carefully set it aside.
  2. Look for a mark indicating the correct water level. However, if there is no mark, make sure the water is about one inch below the overflow pipe. If the water is above the overflow pipe, it will continually run into the toilet bowl.
  3. Find the water valve located on the wall behind the toilet and turn the water off.
  4. Now, check the toilet float to see if it is at the right level. You need to position the toilet float at the water level. If it is not, you need to adjust it.
  5. Moving the float up will increase the water level. Whereas, moving the float down will decrease the water level.
  6. You should adjust the float until the water level is about an inch below the overflow tube.

How Long Should my Toilet Tank Take to Refill?

Toilets typically take about 3 minutes to refill the tank. However, if you want to speed up the refill time you could invest in a dual flush toilet. These toilets allow you to perform partial or full flushes for liquid or solid waste.

Consequently, this will use less than a full tank of water lessening the time needed to refill the tank.