Before you get started, follow the procedures on "How Do I Get a Homeowner's Permit?" When installing a water heater, be sure you follow all of the manufacturer's guidelines.

You must install your water heater in an accessible location. A minimum of 24-inch continuous width and a minimum of 30 inches in height are required for access. You may put the water heater in the garage but you must protect it. Place a fixed barrier like a metal post in the cement between the water heater and where your car would park.

There are additional requirements for gas water heaters. If a gas water heater does not get enough combustion air the flame cannot burn to heat the water. If inadequate venting is installed, dangerous carbon monoxide gas can build up causing illness and even death. It is prohibited for a gas water heater other than those as "direct vent type" to be installed in a bedroom or bathroom unless meeting special criteria. Check for local requirements.

To have a gas water heater, you will need a supply of gas. If you are going to install gas piping or change the gas piping you already have, a separate gas-piping permit must be obtained. The gas piping must not block the removal of the tank. If the gas water heater is in a garage, the pilot light must be at least 18 inches above the garage floor.

Earthquake preparedness:

You must protect your water heater in case of an earthquake by placing seismic bracing on the tank. The bracing must be two 20-gauge sheet metal straps. One strap must be on the upper third of the tank and the other on the lower third of the tank. Approved seismic bracing kits for water heaters are available at many retail outlets.

Expansion tanks:

If your water is on a closed system (the water can flow into your building but not out), an expansion tank must be installed on your water system. The expansion tank is to hold water that can't be held in the water heater after it expands when it gets hot. If there were no expansion tank, the hot water would be released through the pressure relief valve.

Pressure relief valves:

The pressure relief valve is a valve that allows pressure to be released if the water heater gets too hot. The valve connects to a pipe that runs to an approved termination point. The pipe must run the water via gravity to the outside or to an approved drain.