How to Fix a Slow-Filling Toilet Tank

If your toilet won't fill with water, start by making sure the water supply shutoff valve behind the toilet is fully open. Then, check the supply line for kinks, bends, or visible damage. Straighten the line if it is kinked. If the line is bent or damaged, replace it.

You can test the supply line for restrictions if you have a flexible line. Shut off the water, disconnect the supply line from the bottom of the fill valve, and redirect the line into a bucket. Turn the water on carefully and observe the water flow.

There may be a blockage in the line or your incoming water supply if little or no water flows into the bucket. Contact a licensed plumber to diagnose and fix the issue.

If water is flowing normally from the supply line but the toilet tank is still filling slowly, the fill valve is likely restricting water flow.

If the valve is damaged, not serviceable, or more than 5 years old, replacing it is usually the best long-term fix. Shop our toilet fill valves to find the right replacement for your toilet.

If you have a Korky fill valve that is still in good condition, you may be able to restore normal water flow by servicing the valve and removing any sediment or mineral buildup.

1. Turn off the water supply valve and flush the toilet handle to empty the tank of water.

   

2. Remove the refill tube from the valve cover, then pinch the cap to remove it.

   

3. Remove the valve cover by placing your thumb under the tab and lifting. The color of your Korky valve may vary by model.

   

4. Remove the float by gently pinching the float arms toward each other. The float is the piece with an "X" on the top.

   

5. Remove the cap by holding it tightly and turning it to the left one-eight of a turn. Hold the valve body in place while turning the cap to prevent the valve from unlocking. Rinse the cap under warm water to remove debris.

   

6. Remove the supply tube by pulling it straight out of the valve.

   

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

   

8. Reinsert the strainer at the bottom of the supply tube. Then, insert the supply tube back into the valve body.

9. Twist the cap clockwise to lock it back onto the fill valve.

   

10. Reattach the float arms to the valve body. Tap the "X" on the float to make sure it moves freely and does not scrape the sides.

11. Reattach the valve cover and reconnect the refill tube. Make sure the refill tube is clipped to the lip of the flush valve overflow tube. Do not insert the refill tube down into the overflow tube; this can create a siphon and cause the valve to run continuously.

    

12. Make sure the fill valve body is locked in place by turning it clockwise.

13. Pinch the refill tube and cover together one more time to make sure the cap is fully tightened.