Things You'll Need
Replacement refill tube (optional)
When there is not enough water filling the toilet bowl after flushing, it might be necessary to fix the refill tube. The refill tube is near the inside rear of the toilet tank. It connects to the fill valve and distributes water into the overflow tube of the flush valve. Sometimes sediment buildup causes water restriction in the tube resulting in poor filling. Fixing the refill tube in the back of the toilet tank is a matter of either cleaning or replacing the tube.
Turn the toilet water supply valve handle clockwise to stop the water flow to the tank. The supply valve is behind the toilet connecting the water line to the tank and the water line coming out of the wall or floor.
Take off the tank lid and flush the toilet. Grab the end of the refill tube where it connects to the side of the fill valve with your fingers. Twist the end back and forth while pulling it away from the fill valve. The refill tube fits over a nipple on the side of the valve.
Turn the water supply valve counterclockwise slowly until you begin to see water flowing through the fill valve nipple. Do not turn the supply on fully as this causes water to shoot over to the other end of the tank and splash. If the water does not flow through the nipple, the issue is with the fill valve and the valve requires replacement. Turn off the water supply.
Unhook the opposite end of the refill tube from the top of the overflow tube, if water is flowing through the fill valve nipple. The clip simply pulls off the edge of the overflow tube.
Take the refill tube to the sink, and pull the holding clip out of the end of the tube. Inspect the outside of the tube for cracks or damage. If the tube has damage, replace it with a new refill tube available at home improvement centers or hardware stores.
Insert a pipe cleaner into the center of the tube and out through the opposite end. This helps clear any blockage due to sediment or algae buildup. If there is significant buildup inside the tube, or you cannot penetrate through the tube, simply replace the refill tube with a new one.
Push the end of the holding clip into one end of the tube. Push the opposite end of the tube over the nipple on the side of the fill valve. The end of the tube should be flush against the side of the fill valve. Slide the tube clip over the edge of the overflow tube. The end of the refill tube should point inside the overflow tube.
Turn the water supply valve counterclockwise to fill the toilet tank. Place the tank lid back on top of the tank.
Replacement refill tubes and most plumbing supplies needed for repairs are available at home improvement centers, hardware stores or plumbing supply stores.