How to Fix Slow Filling Toilet

Is your toilet tank not filling with water after you flush? If your toilet is filling slowly, there are a few potential causes. The most common is that your fill valve may have internal debris build-up.

For those with a Korky toilet fill valve, you're in luck - our fill valves are 100% serviceable. It may be time to upgrade if you have an older fill valve. Make sure the water supply line connected to your toilet is fully open when installing a new fill valve. A partially open line will limit water flow.

Does this describe your toilet issue?

How to Check the Water Supply Line

When a toilet tank doesn't fill with water at all, start by checking your water supply line. Kinks or buildup can obstruct the water from filling the tank.

If there are kinks in the supply line, simply straighten them out to solve the problem. If the line is bent, you may need to replace it.

You can test the line for restrictions if you have a flexible supply line. Start by shutting off the water and detaching it from the fill valve's bottom. Begin the test by directing the flow of water into a bucket. Be sure to test this carefully to prevent water spillage.

If the water doesn't flow, you may have a blockage in your incoming water supply. Contact a licensed plumber to diagnose and fix the issue.

How to Check the Fill Valve

If your water supply line is working and water is not filling the toilet tank, you need to service or replace your fill valve. Older ballcocks and fill valves may not work as well over time, causing less water flow and slower refills.

Over time, sediment and debris can clog the fill valve. To prevent this and maximize the life of your valve, you should get a serviceable model. A feature of all Korky fill valves is that they are serviceable. If you do not have a serviceable model, we recommend the 2X Long-Life Toilet Fill Valve.

Once you have your new Korky fill valve, check out our guide about how to install a fill valve to learn more. If you already have a Korky model, continue reading to learn how to service it.

How to Service a Korky Fill Valve

  1. First, turn the water supply valve completely open and make sure the supply line is free of kinks. If the water supply line is bent or needs to be turned on, flush the toilet to check the water flow.

Kink in water supply line

  1. If this was not the problem, turn the water supply off.

Shut off water supply

  1. Pinch the refill tube and cover together to ensure the cap on the valve is completely tightened. After pinching, turn the water supply on and flush to see if the valve is working properly.

Pinch refill tube

  1. If this does not improve water flow, turn the water supply off and flush to empty the tank. Make sure to hold the valve firmly through all steps so it does not get turned out of the locked position.

  1. Next, remove the refill tube; you may need to twist it slightly.

Remove refill tube

  1. To remove the valve cover, place your thumb under the tab and lift it up. Please note, that the color of your Korky fill valve may vary by model number.

Remove fill valve cover

  1. Once the cover is off, remove the float by gently pinching the float arms towards each other (the float is the piece that has an X at the top).

Remove fill valve float

  1. Take off the cap by holding it tightly and twisting it to the left one-eight of a turn. The top of the cap looks like railroad tracks. While turning the cap assembly with your free hand, hold the body of the valve in place to prevent the valve from unlocking. We recommend rinsing under warm water to remove any trapper debris.

Remove fill valve cap

  1. Remove the supply tube from the valve by pulling straight and out of the valve (the piece that looks like a wagon wheel).

Remove supply tube

  1. Pull the white strainer from the bottom of the supply tube. Rinse the strainer under warm water to remove any sediment.

Remove strainer

  1. Insert the strainer back into the supply tube and insert the supply tube back into the valve body. Twist the cap assembly clockwise to lock it onto the fill valve.

Reassemble fill valve cap

  1. Once completed, reattach the float arms to the valve body. Pinch the float arms inward to clip them back into place. Tap the "X" on the float to make sure the float moves up and down freely inside of the black box, and is not scraping the sidewalls of the float chamber.

Tap fill valve float

  1. Reattach the fill valve cover onto the valve and connect the refill tube. Ensure the refill tube is clipped to the lip of the overflow tube. Never insert the refill tube down into the overflow tube; doing so may create a siphon and cause the valve to run continuously. 

Attach fill valve cover

  1. Make sure the valve is locked into place by turning it clockwise.

install fill valve

  1. Pinch the refill tube and the cover to make sure the cap is completely tightened. 

Pinch refill tube

  1. Turn the water supply on to test the water flow. 

Turn On Water Supply

How to clean and service a korky quietfill toilet fill valve