Installing a water heater dip tube is a simple project that will require some modest plumbing skills and a few tools. Before you can install a new dip tube you should have purchased a new one. See the article, 'Purchasing a Water Heater Dip Tube' for more information.
Removing the Old Dip Tube
With a new one in hand and the cold water supply unhooked, installing a water heater dip tube is pretty easy. See the article 'Removing a Water Heater Dip Tube' if you have not taken it apart yet.
Installing the New Dip Tube
Put the dip tube into the inlet first. Then you put the gasket back in place.
After that, you put the plumbing pipes back together in reverse order of how you took them apart. The last fitting put together should be the union.
Turn the water on and check for leaks. You will have to wait until the water heater has filled up completely before you are sure that there are no leaks. Open one or two hot water faucets and bleed the air out of the lines.
Starting Up the Water Heater
When you are sure there are no leaks you can turn the power back on for an electric water heater. You will need to light the pilot and turn the gas on for a gas hot water heater. See the articles 'Starting Up an Electric Water Heater' and 'Gas Water Heater Start Up' for instructions on the correct procedures for getting your water heater up and running.
That's all there is to replacing a water heater dip tube. Were you worried? Did you have trouble sleeping last night? Next time, you will sleep like a baby, knowing you can handle a job like this.