The toilet flushes well enough, but the tank takes 10 to 15 minutes to fill. You also hear a slight hissing sound when house is quiet.
This symptom indicates the presence of sediment in the fill-valve diaphragm. This problem can surface after the installation of a new toilet, after work is done on a nearby water main, or after a new well is put into service. The solution is to remove the diaphragm cover and pick the grit from the valve using standard first aid tweezers. This is usually a quick and easy fix. Just remember that sediment can move through your pipes at different rates. You may need to remove is several times before the system is clean.
Step 1: To remove the ballcock's diaphragm, remove the three or four brass screws holding it in place, and lift it up and away. Avoid dropping the screws into the bottom of the tank because the can be difficult to retrieve.
Step 2: Once the cover is removed, lift out the valve's plunger and set it aside. Then carefully remove the diaphragm gasket and look for sand granules or other sediment underneath.
Step 3: Use tweezers to lift out any sediment particles, rust flakes, or other debris. For very small particles, a cotton swab will do the trick. You may need to repeat this repair until all the debris is gone.