Helping you plan your home improvement project, from start to finish

By on Feb 10, 2016
Hot Water Installation

Get up to 4 Free Quotes!

Zip Code

Hot water heaters are one of the many appliances we do not fully appreciate until it stops working. Believe it not, despite its large exterior and solid metal, steel or copper, hot water heaters do malfunction and require replacement or new installation.

While installing a new hot water heater is certainly not a project for the faint, it can be done in one day with the necessary tools and steps. Below, see when it’s time to replace your hot water, how to install a hot water heater and the total installation cost.

When To Replace Hot Water Heater

When to Replace Hot Water Heater

Unlike other prominent appliances around the home, there are a few telltale signs your hot water heater needs to be replaced. If you start to see a small puddle or slow drip under your hot water heater, it’s on its way out. Within a day or two, you should see a trail of water slowly running away from the heater. Either way, your tank has rusted and that can not be repaired. If water is dripping from your hot water heater, replace it as soon as you can.

Additionally, and perhaps even more obvious, is the absence of hot water. However, with this sign, before jumping to conclusions, check with a plumbing professional. Chances are, this problem can be fixed.

Types of Water Heaters

Water heaters run via natural gas or electric. Many homeowners are currently using the traditional tank-style heaters. This tank with a heating element is used to store a reservoir full of water. They are cheaper to install and replace. Tankless electric water heaters are considered an on-demand application for the home. Tankless water heaters tend to be more energy efficient and last longer than traditional heaters.

For more pros and cons of each, please see Traditional Water Heaters Vs. Tankless Water Heaters.

Note: Before buying a new water heater, make sure it meets the Department of Energy efficiency standards.

Types of Water Heaters

How to Install A Hot Water Heater

Tools & Materials Needed

  • Garden Hose
  • Multiple Wrenches
  • Screwdriver
  • Pipe Wrench
  • Plumber’s Tape
  • Tube Cutter
  • Solder
  • Soldering Torch
  • Metal Screws
  • Pipe Connectors
  • Pressure Relief Valve
  • Discharge Pipe

Now that preparation has been covered, it’s time to get your hands dirty. Below are all the steps needed to replace or install a new water heater.

Note: The steps below are specifically for a gas water heater, but installing an electric water heater is very similar.

Step 1: Turn Off the Gas & Water 

The water supply and gas needs to be off. Otherwise, you could have a very dangerous mess on your hands. Find your gas shutoff valve and turn it off. The valve should most likely be at a right angle when off. Next, turn the water off and drain the pipes.

Step 2: Drain the Hot Water from the Tank 

Before removing the hot water tank, we have to empty the tank. You can drain your hot water tank using a garden hose attached to the drain valve. However, as you might expect, the water will be very hot. We recommend using safety gloves or waiting one hour before starting the process.

Then, using two wrenches, disconnect the gas line from the hot water heater. You should disconnect the two at the union where the two lines meet.

Install Water Heater

Step 3:  Cut Off the Water Lines 

Time to fully detach the old water heater. First, unscrew the large vent pipe. All you should need is a screwdriver. Next, using a tube cutter, cut the hot and cold water lines. For some operations, you may just have to unscrew the unions with the same wrenches from before.

Remove the old water heater completely out of the way.

Step 4: Attach the New Relief Valve 

Take your new temperature and pressure relief value and wrap the end with plumber’s tape. Place the valve in the new hot water heater and screw it in with a pipe wrench. Attach a new copper pipe to the relief valve.

Step 5: Attach Connectors

Next, we have to attach new copper adapters, or short copper tubes, to the new hot water heater. Before attachment, some add plastic connectors to protect against galvanized pipes. These plastic connectors may be required by code, but it is not 100% necessary.

Now, take the two new adapters and screw them into the hot and cold water inlet ports.

Step 6: Attach All Pipes 

Get up to 4 Free Quotes!

Zip Code

With the copper connectors in place, we can attach all pipes to your new water heater. Place the new water heater directly under the previously cut pipes. You may have to recut or extend the old pipes. Solder, or attach the pipes to the new water heater using heat from your soldering torch (any heat source can work).

Do not solder any fittings directly on top of the water heater. If you do, you could melt imperative plastic parts and damage your new water heater. That is why we installed those connectors first. Furthermore, you can solder your pipes before attachment as well.

Note: Soldering takes practice. If this is your first soldering project, consult a professional.

Tankless Water Heater

Step 7: Reconnect the Vent

Now, reconnect the vent using appropriately sized metal screws. If you are unsure, take a picture of your vent and head to your nearest Home Depot. The vent should not be placed directly on the hot water heater. It should attach right above the draft hood.

Step 8: Reconnect the Gas Lines

Coat the end of the gas line with plumber’s tape and attach it to another plastic nipple. Using two pipe wrenches, just like we did before, reconnect the gas line to the new water heater. You should finish with the union, the actual connection point.

Step 9: Fill the Tank

Before we are complete, we have to fill the tank and make sure all is working. Close the drain valve (the same point you used to drain the old tank). Turn your water back on and open the cold water valve. Turn a hot water faucet on and let it run as you are refilling the tank. Once the tank is full, turn off the faucet and check the discharge pipe on the pressure relief valve to be sure it isn’t leaking.

Note: Make sure your tank is full before turning water back on. Both electric and gas water heaters running on non-filled tanks can cause damage and repairs will be needed.

Step 10: Check the Vents

According to Family Handyman, most water heaters rely on a natural draft to draw combustion fumes up the flue. These fumes must stay within the draft. After changing your water heater, you should check this draft.

First, open or turn on a hot water faucet until you hear the gas burner in the water heater ignite. Then, light a match and place it near the draft hood. The smoke should head up the hood. If not, you should content a plumber.

Water Heater Cost

Step 11: Light the Pilot Light

Time to light it up, but before doing so, double check with the manufacturer's directions. Set the temperature to 120°F. Test the water as well as possible leaks again.

Removing the Hot Water Heater

Most water heaters are quite large. Many homeowners will just ask a friend to help, but others with electric saw experience can cut the water heater in half using safety goggles and protective gear. A smaller water heater is always easier to remove.

Hot Water Installation Cost

Despite their utmost importance, hot water heaters are not as expensive as most assume. As noted before, traditional hot water heaters have a lower initial cost than a tankless water heater. Whether you choose a gas or electric hot water heater, expect the average price to hover around $800 with installation. However, installing yourself can save almost half that cost.


Installing a hot water heater is not a project for the faint, but with precise hand coordination, you too can save $500 the next time you have to replace your hot water.

As always, there are basic preventive items you can take to ensure your water heater lasts. As such, please see DIY Tips For Water Heater Maintenance.

Get up to 4 Free Quotes!

Zip Code
2016 JDR Industry Blogger Award Winner for Best Microblog

You've spent some time with us! How about sharing the love in a Google review? Leave us a review