Lowe's Home Improvement

How to Fix a Slow-Filling Toilet

Learn how to fix a slow-filling toilet with these simple plumbing tips.

Finding the Slow-Filling Toilet Problem

A slow-filling toilet tank is a relatively common problem. Depending on your water pressure, a tank usually refills in about three minutes. 

Make sure that the water shutoff is completely open for maximum water flow. If that doesn't help, you may need to clean the pump and valve.

Sometimes there's buildup in the valve, so cleaning should help open it up. If the fill valve seems to be working fine, there might be a bigger plumbing issue at hand. If your water supply is flexible, shut off the water and disconnect the line. Place the line into a bucket and turn the water on. If the water pressure is low, there may be an issue elsewhere in the water line. If so, call a professional.

Your problem could be resolved by simply replacing an older-style ball cock assembly with a new fill valve and float cup assembly.

Good to Know

To clean the fill valve, turn the water off, remove the valve top and cover the opening with an inverted cup. Hold the cup over the opening and turn the water back on to clean the debris.