- 1). Shut off the water supply for the tank you wish to remove. Look for the water shutoff valve mounted on either the wall or the floor underneath the tank. Rotate the knob on the end of the supply valve to the right and cut off the water.
- 2). Remove the toilet tank lid. If this is a dual-flush toilet, first unscrew the push button flush device mounted on the top of the tank first. Set the lid to the side.
- 3). Press down on the handle and flush the toilet. For a dual-flush toilet, press one of the buttons on top of the siphon in the center of the tank. Wipe up any remaining water inside the tank with a sponge, once you've flushed out all the water inside.
- 4). Place a dry towel on the floor underneath the tank. Use a pair of pliers to loosen the water supply coupling connecting the water supply hose to the tank.
- 5). Loosen the nuts on the tank bolts on the underside of the tank, using the adjustable wrench.
- 6). Remove the tank from the toilet bowl drain by lifting it straight up and off the bowl.
Source...