Why Does My Toilet Make A Loud Humming Sound When I Flush It?

The shutoff mechanism inside the tank may not be seating down fully enough to shut the incoming water supply off completely. The water pressure is 'squeezing' through the minute gap which is not fully in the closed position. The float that when it rises with the water level activates the mechanism, either a empty ball at the end of a long arm or a hollow cylinder with a center opening which travels up & down the tall vertical pipe, that by means of a wire arm triggers the water shut-off.

Depending on the type of the float; bend the long arm attached to the hollow ball downward so the ball is closer to the bottom of the tank. Do this move gently and the use of both hands, the left hand holding the connection to the arm at the top of the vertical supply pipe in a way to stop any movement, this while the right hand is slowly and deliberately bending the long metal wire down. Another solid plastic style arm will not need any bending but is adjusted by the screw on top cap at the vertical supply pipe. The third hollow cylinder which travels up and down the vertical supply pipe, pitch the "V" clip on the vertical wire rod that is parallel to the drain pipe. While pitching the clip move it up towards the top of the wire. Good Luck, I am
tired of explaining the many options for all the types of shutoffs.

The filled water line is coming up too high and overflowing down the center vertical drain tube. There should be a "Fill to" Line casted into the inside of the ceramic tank interior, that is where the tank should be filled to and then shut off completely.

P.S. Is it at all possible the Water Closet is stating an unsolicited opinion on a all vegetarian diet?

Bad main valve in the tank. Replace it.

I had found a small water leak under my kitchen sink where the  water line hooks up to the hot water faucet. I have a lot of hard water deposits that have always been a problem,they build up and eat away at the materials,till it breaks.I attempted to put some bonding around the leak & it seemed to stop leaking. I still have the noise. Someone told me its not completely sealed and if it can suck air at all it will cause a noise like I described. Does this seem like the case? That the noise is from an air leak in the water line?

2 things--

1- Bad ballcock washer(replace Ballcock)

2-Bad closet supply washer

Sounds like it's time to upgrade your toilet. I would recommend 1 of the toto toilets if you aren't sure which is a good brand.

It's always possible someone went in there, layed a big cable then realised there was no bog roll, then used their pants and stashed them in the cistern in a panic.
 
come on, we've all been there.