When flushing thetoilet tank shoots water under tank

Hello, Tammy -

This article from the San Francisco Examiner (newspaper) should be instructive:
http://homeguides.sfgate.com/highpitched-noise-toilet-fills-back-up-water-85163.html

This YouTube video may prove helpful:
https://www.youtube.com/watch?v=IT51OslBQsA

Best wishes.

the fill valve is not letting water in you either have a float that raises up when water is full so when you flush the float drops down letting water in then when water raises it shuts off i would replace the float fill valve and corky flapper.... here is what you do .... first shut water off where it goes up to the tank....... flush commode to empty as much water from tank....... reach up under tank there is a plastic coupling that connects the water supply line to the bottom of the toilet tank...put a small pan under the shut off valve that goes to the toilet some water is going to drain from the tank when you take the coupling loose..... turn the coupling counter clockwise ( use a channel lock adjustable wrench to loosten then had turn) once this is loose you can pull the riser tube away from the tank...... now there is a plastic nut that screws the shaft to the bottom of the tank loosten with channel lock then remove with hand by turning counter clock wise ( you will get a bunch of water flowing down to the pan) remove the entire fill valve , replace with a fluidmaster fill valve ( about 8 bucks from big box store when you take the new fill valve out of the box there is a neopreme seal you must put on the new threaded shaft ( it has an inner ring you may have to punch out) once you put this on you can insert the entire shaft down through the hole in tank then secure with thin nut provided tighten but do not overtighten then put coupling back on,,,,,put the over flow tube on the tit of the fill valve and stick down into over flow ok thats done when you go to big box store purchas a 5 buck corky flapper (red caus it can handle chlorine water better) remove the old one at bottom of tank( just two clips to remove and chain attached to flush lever...install new one be shure chain does not have a lot of slack so it does not fall under flapper seal when you flush......OK YOU ARE DONE TURN WATER ON WATCH TANK FILL LOOK FOR LEAKS TAKE A TOWEL AND DRY ALL AREAS THEN TAKE YOUR HAND AND FEEL FOR LEAKS UNDER TANK AND DOWN TO SHUT OFF VALVE .....CONGRATS YOU DID IT!

Run a tank of 50/50 water and white vinegar through the steam cycly. Run two or three more tanks of plain water. This should clean it out safely.

If you take off the top lid of the tank you will probably see a little small hose that is unattached. If you flush, water will shoot out of that little hose. The hose should be sticking down into the tube (cylinder) that stands up in the tank and shooting the water down the cylinder. It should be attached to the top of the cylinder by a small clip.

Hose in tank it has a clip to secure it to a fill tube in center of tank to let water fill down tube . If it is just stuck down in it or loose it has to much pressure and will spray every where.

Is the fill line in the tank loose? Does it just shoot water into the tank itself? I had this issue until I realized the while fill tube is supposed to be pushed into the black cylinder/small plastic tube in the middle of the stopper assembly. After i pushed the line into the tube, the bowl would always only fill a little bit. Now it fills almost a 3rd of the way up the bowl and doesn't bubble during flushes.

if the toilet is old or not cleaned proper, the water jets that shoot the water into the bowl might be clogged. If the jets are clogged with moldor hard water build up the toilet will not flush proper. If you can take a 3 gallon bucket of water and pour straight into the bowl and it flushes fine you have a water pressure problem as described above. the problem also might be that your water inlet system is not letting in enough water to fill the tank. If this is the problem you need to replace the water inlet mechanisim, such as a fluid master. If you use a blue water device that hangs on the side of the tank in the back of the toilet you might have a peice of it under the flapper that takes the water to the bowl when being flushed. Check under the flapper if you put cleaners in the tank.

I believe you have a high water pressure going to the
tank. Minimize the water volume going to your tank. This is done by fully closing the inlet valve under the tank. Then open about 1/4 to 1/3 of the inlet valve. To do this, count the number of turns to get it full close from full open position. For 1/4, divide the number of turns by 4 and divide it by 3, for 1/3 open. Hope this will solve your problem.

There is a shut off valve under the stool. turn the water off and go to walmart and get a new valve. Take the one out of your stool so you get the right one. hope i was helpful

is the black thing between the the tank and the bowl?
if so, go to any of the home center or plumping store for the seal.
shunt off the water and unbolt the 3 bolts that holds the tank to the bowl from the buttom. you may need a flat screw driver to help hold the bolts. pull up the tank slowly, and lay it on the side, replace the seal, reseat the tank on to the bowl and tighten the bolts. make sure all bolts are equal pressure and the tank is level.