How To Install A Water Heater

Need to Hire a Plumber?
Get a free estimate online from top local home service pros in your area.
Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

No home is complete without its essential appliances, and one of the most important ones is the water heater.

A water heater is a gas or electricity-powered device that generates heat energy to warm up your showers. Commonly, we ask handypersons or plumbers to attach and install water heaters in our house.

However, the process of installing one is not as complicated as it seems. Let’s dive in and find out more about how to install a water heater (see also our guide on how to drain a water heater).

What tools do you need to install a water heater?

what tools are needed for install water heater

Here is a list of all tools and materials you will need to install your water heater setup.


  • 4-in-1 screwdriver
  • Adjustable wrench
  • Electrical tape
  • Pipe wrench
  • Plumbers tape
  • Soldering torch
  • Tape measure
  • Tube cutter
  • Wire cutter
  • Voltage tester
  • Safety goggles


  • Discharge pipe
  • Fittings
  • Pipe thread compound
  • Pressure relief valve
  • SolderThe TPR valve is supposed to control the temperature and pressure (see also ‘How To Adjust A Pressure Reducing Valve‘) inside the storage tank and keep it from shooting to dangerous levels. Venting pipe and connectors
  • Water and gas piping

Getting Started

getting started to replace water heater

The general steps to replacing or installing (see thermostat) most water heaters are roughly similar, irrespective of the heat source. We will discuss the steps to replacing a gas-powered heater here, but installing a propane heater or an electric heater is practically the same.

There are quite a few reasons behind installing a water heater. You are either adding it to your home for the first time or are replacing it because your old one started giving trouble.

You can sense the signs that your heater has come to the end of its life when it starts leaking water under the tank in a slow drip. You may even notice that the water is rusted. That means the tank has rusted on the inside and needs to be replaced.

When you notice the leak, get down to replace the heater immediately. However, for any other problem, consult a plumber first since the problem might be fixable. Even when you decide to replace your heater, contact local authorities or plumbers before you get started.

You might have to undergo inspections or need permits. After sorting through all the necessary paperwork, you can get racking on installing your new water heater.

Let’s look at some of the essential parts of a heater:

  • Storage tank
  • Burner
  • Thermocouple
  • Heating element
  • Anode rod
  • Dip tube
  • Temperature and pressure relief valve
  • Drain valve
  • Thermostat
  • Gas supply valve
  • Flue pipe or vent

Step-by-step rundown

Shut off gas and water valve

turn off gas and water valve

The first step in this process is to turn off the water and gas valves. These are the pathways that bring water into the storage tank and gas to the burner.

These valves need to be shut before you dismantle or take away pieces from your heater. The gas valve should be located close to your heater, and you can close it by rotating it a quarter turn so that the valve is perpendicular to the gas pipe.

Once you shut off the water valve (see also our favorite automatic water shut off valves), make sure you drain the existing water from your plumbing by opening the lowest faucet. That way, all the water in the heater pipes is removed, and you can stay dry.

Drain the water and remove the gas pipe

Find the drain valve on your water heater, and connect it to a garden hose or thick-skinned pipe. The pipe will drain the water from the heater’s storage tank. Keep a safe distance from the drain valve and the pipe because the water will be scalding hot.

Using a pair of wrenches, disconnect the gas line at the nearest union, and then remove the pipe from the gas valve using a pipe wrench. With this, you will have separated your gas control valve and the gas pipe.

Separate the heater body

wrench for remove pipes

The next goal must be to separate the water heater body from the water inlet and outlet. To do so, first, detach the vent pipe from the top of the heater and move it aside.

You should be able to do this using a screwdriver. Next, find the nuts on the cold and hot water lines and detach them from the heater. If there are no nuts nearby, use a tube cutter to cut both pipes.

Now, you will be able to slide the old water heater body out of the way. Ensure that you mark each line with a label of some sort to prevent confusion later.

It is essential that you take adequate safety precautions during any cutting episode since a gash from any rusted material can be a potential health risk. So, take utmost care if you are planning to cut the tubes.

Prepping the new heater body

Check your new water heater for a place to install the temperature and pressure relief valve (TPR valve). Get your new TPR valve, and wrap its threads with Teflon tape.

Then, fix it tightly into the heater body using a pipe wrench. The TPR valve is supposed to control the temperature and pressure inside the storage tank and keep it from shooting to dangerous levels.

Lastly, attach a copper discharge pipe (see also ‘How To Connect PVC To Copper Pipe’) to the TPR valve that runs along the length of the heater and joins the plumbing on the floor.

Attaching new pipe systems

join copper pipes

Copper pipes that are 6 inches in length need to be soldered to ¾ inch copper connectors. Then, this assembly is connected to the hot and cold water lines on the new heater body.

The copper pipes you soldered are tailored to fit into the cold water inlet and hot water outlet easily using a wrench. Use Teflon tape at the point where the lines are connected to the copper pipes to eliminate any chance of leaks.

Some plumbers will also add short plastic-lined nipples to the cold and hot water lines on the heater’s body before connecting them to the copper rods. That way, the copper rods, and the heater body are both safe from internal galvanization or corrosion.

Rejoining the water lines

rejoining water lines

Remember the water tubes that cut off in the initial steps to detach the old water heater body? It is time to join them in the new heater body.

According to the previous step, your water heater body has 6-inch copper pipes attached to its top. Now, our task is to connect these two pipes to their respective cold and hot water lines. The labels you put earlier on the cold and hot water lines will tell you which tube goes where.

You will have to solder the copper pipes into place. There might be impending height issues with the pipes, i.e., you may have to add copper slip couplings between the two tubes’ ends and solder them in place.

Cutting If you follow all the above steps carefully, you will be able to solve your water heating woes with ease.and using the perfect amount of copper coupling is tough; it is challenging to get the height just right. Additionally, use Teflon tape at all soldered joints to prevent leaks.

Reattach the vent pipe

vent pipe

The center of the top on your new heater body will have a draft hood. This hood needs to be connected to the vent pipe, which is responsible for flushing out exhaust gases into the atmosphere.

The vent pipe is connected using ⅜-inch #6 sheet metal screws, holding it in place over the draft hood. The holes for these screws need to be drilled before placing the vent pipe in place.

Quick necessary tip – let the vent pipe rise upwards straight for at least 12 inches before making its first bend or curve. Ensure that the vent pine is fitted correctly over the draft hood between the hot water outlet and cold water inlet.

Installing the gas control valve

Here comes the most critical part of the water heater – the gas control valve. It is the one organ that is responsible for the actual heating process.

You have to fix the gas control valve to the gas line near the heater body. Coat the threaded ends of a pipe joint with a lubricant compound (pipe joint compound) to avoid stressing the gas valve. The fist nipple should join the gas valve easily.

Use two wrenches to connect the pipe to the valve. Fix the open end of the tube to the gas line. You can join it to the elbow from where we disconnected the old gas valve. Enforcing the connections between the gas valve and the gas line would complete the piping structure of your new water heater.

After this, it is vital to check the water flow in the water heater system you just installed. Turn off the drainpipe valve, and open the main water line, so that water flows into the heater tank from the cold water inlet.

Then, open the nearest hot water faucet and let the water flow continuously. Once the water comes out of the hot water faucet, check all joints and fittings for leaks.

Check for a backdraft

Your new water heater has now been installed. It is only a matter of getting through a few quality checks before you can enjoy it. The most critical aspect of a heating system is the working of its venting system.

The vent pipe is designed to suck in the poisonous exhaust gases from the burner and chuck them out. You need to ensure that it is working well because any leaks in the vent duct would spell out danger for the house.

Close all doors and windows of the room where the heater is located. Also, switch off all fans and air conditioning. Then, open the main water valve and the hot water faucet. You should hear the burner generate heat.

Now, light a matchstick and hold it next to the draft hood on the top of the heater body. Observe the smoke from the matchstick. Ideally, the smoke should move into the vent pipe automatically. If the smoke does not flow into the vent pipe, it means there is a backdraft in your flue pipe. In such situations, it is wise to contact an experienced plumber and get the vent checked.

Check for leaks

safe method to check gas leaks

Arguably the most crucial check in this process, the leak check will determine if you can use your heater or not. The method of checking for gas leaks is relatively easy.

Make a mixture of equal parts water and dishwashing liquid and brush it over the joints in the gas line. Also, cover the elbows joining the gas valve and the gas line. Now, turn on all systems, including the main water valve, the gas valve, and the hot water faucet.

Then, observe the mixture you applied to the joints. If it bubbles, it means that there is a leak in the joints. In that case, tighten or fix all the joints connected to the gas line. Wipe the joints dry, and contact a plumber or a professional handyperson to oversee and check all your work.

Ignite the pilot light

The pilot light is located on the bottom of your heater’s body. Use a lighter to ignite the pilot light. There should be clear instructions on the product packaging of your water heater about the pilot light. Finally, set the temperature to 120 degrees F on the thermostat.


Replacing or installing a water heater in your home is not a very difficult task. Every average joe can manage the feat with the right set of tools and guidelines.

If you follow all the above steps carefully, you will be able to solve your water heating woes with ease. There are a few steps where you have to use cutting, soldering, and joining tools very carefully, but those are still doable tasks, albeit with an excellent precautionary safety setup.

The instructions above are related to installing a gas-powered water heater. However, we can promise you that similar – if not the same – steps will also help you install any other water heater. The hardware of all water heaters works in the same way even though the heating elements and the fuel sources change.

All water heaters need a pipe through which cold water flows in and another pipe through which hot water flows out. Lastly, they all need a pipe to take care of the exhaust gases. As we said, it is not as hard as you think.

Reference articles:

Need to Hire a Plumber?
Get a free estimate online from top local home service pros in your area.


On Key

Related Posts

Is Drano Bad for Pipes? The Truth Revealed

Need to Hire a Plumber?Get a free estimate online from top local home service pros in your area. Note: This post may contain affiliate links. This means that at no cost to you, we may