If your toilet will not stop overflowing, turn the shutoff valve behind it clockwise first. If that does not work, lift the tank lid and raise the float to stop the water from filling. If water still keeps coming, close the main water valve for the house, and do not flush again until the toilet has been repaired.
Why It Keeps Going
A toilet that overflows once is usually clogged. A toilet that will not stop overflowing usually has two things going on: a clogged drain and a fill valve that is not shutting off. The tank keeps filling, the water spills through the overflow tube into the bowl, and the bowl cannot drain.
Shutting It Down
Try these in order:
1. Turn the oval valve near the floor behind the toilet
2. Lift the float arm or float cup in the tank and hold it up
3. Push the flapper down so the tank water stays put
4. Close the main water valve for the home
Once the flow stops, you have time to clean up and think.
After the Water Stops
Wear gloves and soak up the water with old towels. Wash the floor with soap and water and disinfect it. If the bathroom is upstairs, check the ceiling below over the next day for a wet spot.
What Needs Fixing
A stuck fill valve usually needs to be replaced. The clog may clear with a flange plunger, but if it does not, or if other drains gurgle when you flush, the blockage is deeper.
Do not use chemical cleaners in a toilet that is already full.
A plumber can replace the faulty fill valve and clear the clog so the toilet works normally again. If your toilet is older, talking through a toilet upgrade may be worthwhile. Call JPR Plumbing at (833) 603-1840.