Why is Your Toilet Tank Not Filling and How To Solve It?

toilet tank not filling

Last updated on January 13th, 2022 at 07:28 pm

You might be annoyed and ask yourself why toilet not filling up? Since the toilet tank is a technical device, you may encounter various strange problems, and not filling is one of the common problems. 

The Toilet tank is designed with an auto water refill system even it needs only a few seconds to fill after each flush. If your toilet tank not filling with water after flush, there might be a faulty valve, wrong water float, and cracked flapper valve. 

This guide has come with solutions of the toilet not filling details, and you will know how to fix a slow filling toilet tank. 


Why Your Toilet Tank Isn’t Filling?

There have some common issues of not filling a toilet tank. If you can make sure about that reason, maybe you can solve the problem by yourself. 

Faulty fill valve:

The fill valve works to control the tank water level. First of all, We observed the float position in an extremely low position in the tank. If so, then it could close the water supply to the toilet tank for a temporary period. 

Defective flapper:

A defective flapper can reduce the water flow from the tank to the bowl. Which also can shut the tank filling, or you might face toilet tank filling slowly. We recommend checking the flapper in two ways. The ways are checking for cracks and fungal built up inside the tank. 

Defective Fill Valve:

If you can make sure that the flapper is not faulty, there must be a problem with the defective fill valve. The fill valve is situated inside the tank with a vertical tube shape. It works for controlling the water level of the tank. But with time, the fill valve could be stuck with accumulated debris which can block the fill valve. 

How to fix a toilet tank not filling at all

Here are given some solutions, including the most common problem’s solutions. You can try these tested processes to eliminate the problem of no water in the toilet tank.  

toilet tank not filling at all

Adjust the fill valve

Any toilet tank must have a float ball, cup, or cylinder. The float ball is larger and used in the old model toilet. On the other hand, the float cup is used in the modern toilet and smaller. Good to know that float is connected with the fill valve to control the valve opening and closing. 

Step 1: 

Press the shut-off valve and stop the water supply line and turn it in a clockwise position. Now hold down the trip lever as much as possible and press the flush button so that maximum water can get out. 

Step 2:

Take off the tank lid and observe if there have a float ball or float cup. Don’t forget to keep the lid in a secure place. If you get a float valve, find the connecting point of the float arm and fill valve. Now turn the connection point clockwise to increase the water level. 

Step 3:

If there has a float cup, then you will get a plastic screw. You also have to use a screwdriver to turn the float cup clockwise to increase the tank’s water level. 

Last step:

Keep in mind to avoid the tighten the screw so much. Continue the turning, opening, and closing process until the toilet tank water level would be ½ of the overflow tube. 

Replace the fill valve

The fill valve and water supply line is directly connected, and it works to refill the tank after every flush. It also has a connection with the refill tube and floats. If the fill valve has any defect, then the toilet won’t fill up with water. A fill valve often stops to supply water from the line to the tank because it might have stuck with a long-lasting debris accumulation. You can fix your fill valve or replace it with a new one. 

The fixing process of fill valve:

At the very first, shut off the toilet water supply and press the flush button. Use one hand to hold the fill valve shaft and turn the fill valve cap 1/8 counterclockwise with another hand. Then check the valve holes if there have any accumulated debris. You can hold a cup on the fill valve which reduces the water splashing. When you notice that all debris is cleaned out by water force then keep the fill valve in the same place again. 

The replacing process of fill valve:

Shut off the water supply line as usual. Then press the flush button. Hold the trip lever as much as strongly so that enough water can remove. 

Hence, disconnect the water supply and turn the connected coupling clockwise to remove the lock nut from the anti-clockwise position. After then you need to remove the added refill clip from the overflow tube. 

In this step, clean the fill valve place properly. Now the new fill valve sits on it and attaches the screw nut very well. Reconnect the water supply line and connect it to the overflow tube.

Replace the toilet flapper

Suppose you notice that your toilet tank not filling but water running then it is a sign of a defective flapper. The flapper is rubber-made, which works to reach the water from the tank to the bowl and hold the water for further flush. 

Step 1:

You will get a shut-off button to stop the water supply line. So, stop the water supply first. Next, pull the trip lever with enough pressure and press the flush button. 

Step 2:

A lot of water will remove due to pulling the trip lever. Now remove the lead and keep it in a safe place. At the same time, disconnect the lift chain from the arm. 

Step 3:

There have some pegs connected with the flapper. Now remove the pegs from the overflow tube and clean the areas where the new flapper will be installed. Then install the new flapper and connect pegs with the overflow tube. And connect the lift chain and handle arm. Finally, check the tank if it is filling properly. 

Replace the overflow tube

Overflow tube refers to the larger tube situated in the middle of the tank. This tube has a channel with the toilet bowl, and it can send excess water to the bowl for reducing the overflow. Even it can down the water flow to the bowl despite being crack often. As a result, you will face the not filling but running water problem. Overflow replacing is as easier as you don’t even think. You have to take off the flush valve and set the new one. 

Check the toilet water pressure

If you observed that your toilet tank is filling very slowly, it means the water pressure is low in the toilet. It might happen for two reasons like pipe clogging and leaking. It is recommended to check out another water supply line in a home. If it happens only in the toilet, make sure that there is no problem inside the pipe. In this case, you can call a plumber. 

Open the shut off valve

Sometimes, the toilet tank not filling problem might happen for a closed shut off valve. You can check out the shut-off valve as well as another issue. The shut-off valve will get behind the toilet tank. If the valve is closed, then turn it counterclockwise. 

Final Words:

Hope you got the primary points of why toilet not filling and how to fix all of the problems of a not filling toilet tank. If you have faced different problems from our listed issues, you can contact a plumbing service company because there might be serious plumbing issues. If you feel this guide is helpful for you then share it with others. 

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