Water carries minerals that deposit on the inside of the pipes. Over time, this slows down the flow of water. Hot water, because it sits in a hot water heater, carries minerals, grit and sometimes even rust that clogs the hot water lines faster than the cold water lines or one faucet more than another. Running the water backwards under pressure cleans these deposits from the line. When the hot water in one faucet runs slow, it a simple matter to back-flush the hot water line and free the pressure,
Turn off the hot water heater. Close the valve leading from the hot water heater to the rest of the house. You may need a wrench to make sure the valve is completely closed.
Open the hot water valve on a faucet that runs well. It can be a sink or bathtub faucet. Only the water from the pipe should dribble out. If the water continues to run after five minutes, tighten the valve on the hot water heater.
Unscrew the aerator from the faucet that is running slow. Place a dime over the mesh and screw the aerator back into place.
Turn on the hot water on the faucet containing the dime. Turn on the cold water. No water will come out of the faucet because it's blocked with a dime. Instead, the water will flow backwards through the hot water pipes and pour out of the open faucet. Allow the water to run freely for several minutes.
Turn off the cold water. When the water stops flowing from the open faucet, unscrew the aerator and remove the dime. Screw the aerator back in place. Open the valve from the hot water heater and turn the unit back on. Test the water flow in the formerly slow faucet.