Safety Tips For Water Heaters. If You Aren't Sure, Ask A Professional

Some work that can be done to improve your water heater's situation can be done by a homeowner.  Other procedures require a plumber's help or an electrician.  Only perform work on a water heater if you're comfortable that you know what you're doing.
Before doing plumbing work you must perform these safety steps:
Turn the electricity off if you have an electric water heater or turn the gas control knob to PILOT if you have a gas water heater.
Find the cold water line on top of the water heater and turn the gate valve off.  The cold line is the line on the right as you are facing the water heater.
Open a hot water line in a sink in the house.  This relieves pressure on the lines.
Open the drain valve on the water heater.  It's located at the bottom of the water heater and looks like a hose bib.  Drain out a gallon of water from the water heater, so it's not completely full at the plumbing connections on top.
Tell everyone in the house or building to use cold water only.
Whenever removing electric elements on an electric water heater, be sure that the electricity is turned off.
Whenever replacing the drain valve on a gas or electric water heater, be sure to turn the gas control knob to PILOT or to turn the electricity off.
Check the gas connections on your gas water heater by spraying liquid glass cleaner on them.  If you have a gas leak.  The glass cleaner will spit and foam slightly if you have a gas leak.
Be careful your gas water heater does not backdraft back into your house.  When the gas fumes from a gas water heater travel up and out the draft diverter on top of the gas water heater, they go to the outside of your house through a vent.  The fumes can sometimes be pulled back into a chimney flue, an open window, or an air conditioner.  If you smell fumes inside the house, call a plumber immediately.
If you are insulating your pipes for your water heater, do not cover dielectric unions, fittings, or copper flex lines.  Future leaks from the pipes will cause more damage because of the insulation.  Do not insulate the tin draft diverter on top of a gas water heater.  The insulation can ignite.
If you have a recirculating loop for your water heater, consider installing ball valves at the connection point to the water heater. If you have a pump on the line, install a ball valve before the pump as well.
Again, if you are not certain of your ability to work on a water heater in any way, get a professional service technician to help you.