You can conserve water by installing a toilet with a push button flush valve. The push-button valve has two buttons, one for small flushes for liquid waste and another for solid waste. Both buttons can be operated simultaneously. The button has two push rods underneath that activate the flush valve. You may need to adjust a push button flush valve when the toilet doesn't flush all of the waste as it should. The part of the push button that usually requires adjustment is the side that controls the flush for solid waste.
Remove the toilet lid from the tank and place it upside down on top of the toilet seat.
Turn the lock nut securing the white threaded rod counterclockwise, using your fingers. There are two rods on the push button. The blue rod opens the small flush valve and usually requires no adjustment.
Grasp the white threaded rod with your fingers and turn it once counterclockwise. Retighten the lock nut with your fingers.
Place the lid back on the toilet tank and test the push button. Adjust as necessary until the toilet flushes completely.