To user the water in your pipes: let air into the plumbing by turning on the faucet in your house at the highest level. A small amount of water will trickle out. Then obtain water from the lowest faucet in the house.
To use the water in your hot water: tank be sure the electricity or gas is off and open the drain at the bottom of the tank. Start the water flowing by turning off the water intake valve and turning on the hot water faucet. DO NOT turn on the gas or electricity when the tank is empty!