You will need
- Toilet cistern, valves, requiring replacement.
Define the exact purpose of the adjustment of the drain of the toilet. What you want to achieve: reduce the amount of flushing water or, conversely, to increase it, or need to adjust the constant drip of water?
Change in the amount of water drained from the reservoir. Open the lid of the toilet tank. Adjust the float so that it overlaps the inlet when the water reaches the desired level.
If the water from the tank flows continuously install the problem. Look under the toilet tank lid and verify that float and drain valve are straight, have no bias. If necessary, correct their position, and the drain will be adjusted.
If that doesn't work, find where the cause of the water leak. In modern cisterns the water often flows through the overflow tube. Change the angle or height of the float by bending the yoke so that the water level in the reservoir was slightly below the top edge of the overflow pipe.
Check the inlet valve. Lift the float up until it stops. Valve connected with the float by means of the rocker should shut off the inlet valve fully. If water continues to leak, replace the faulty inlet valve with a new one.
Turn off the water. Unscrew the Union nut of the water fittings to the reservoir and the nut of the valve. Remove the valve. Then install the new in reverse order. Turn on the water, check the inlet valve.
If the tank is old design, he may stop to keep water drain valve. Tweak its position or adjust the fit of the "pear". Turn counterclockwise the plastic threaded fasteners drain button valve tightly blocked drain.
Adjust the valve with a new one if the drain valve is worn out, and adjustment does not work.
Call a plumber if you can't handle the drain from the tank.