Why is there a loud humming noice after the toilet is flushed?
Fixing a toilet is one of those things that you have to take the lid off the tank, flush, and watch happens. Toilets work quite simply. When you flush you pull on a lever that pulls a chain and lifts the flapper at the bottom, draining the tank. When the tank is empty the flapper closes and the water enters the toilet though the cylinder shaped flush valve. When the water gets to the top it raieses the float and turns off the water, and you're ready to fush again.
My guess is that the toilet is humming when the water is filling up though the flush valve. Minerals build up on the inside of plumbing pipes in your home and can break loose. These minerals could be partially blocking the flush valve and creating a hum. Is the toilet filling slower than usual?
If you feel confident you can change the flush valve ourselve.
Tools: Channel lock pliers, large bowl or ice cream bucket.
1. Turn off the water to the toilel. The tap will be on the bathroom wall or floor behind the toilet. If you have a Tap Vlave: Turn clockwise to shut off. When you turn it off valve don't over tighten it, you can damage the o-ring. If you have a Ball Valve: It will only turn a quarter turn to shut off.
2. Flush the toilet so don't have to work with a tank full of water. Note: The inside of a toilet tank contains fresh water.
3. Take off the hose end that is mounted on the bottom of the tank using a pair of channel lock pliers. Turn it counterclockwise. Be prepared to catch the water that is in the hose with a bowl.
4. Take off the nut that is attached to the flush valve at the bottom of the tank using the channel lock pliers. Again be prepared with a large bowl or ice cream bucket to catch the remaining water in the tank. Remove the flush valve from insie the tank and let the tank water drain into the bucket.
5. Now take the flush valve to your local hardware store and get a similar one. Ask for help if you need it. Make sure you read the instructions when you install the new flush valve, it's basically the reversed of taking it off.
The secret to plumbing is never over tighten your water connections, you will damage the fillings. Make it hand tight then tighten it with a pair of pliers or a wrench only a quarter turn. Turn on the valve and check for leaks, if it leaks give it another quarter turn.
I hope that helps. Trevor.