Informational Guide

How Much Does A Water Heater Weigh?

We take a look into the factors that impact the weight of water heaters and closely examine the question, how much does a water heater weigh?

by Josh Mitchell

Whether you plan on doing a DIY installation or you hire a professional to install or service your water heater, it’s a good idea to know how much it weighs. This is a crucial home appliance, and the steps for proper installation and maintenance depend a lot on your water heater weight.  

In this guide, we’ll be looking into the factors that impact the weight of water heaters and closely examine the question, how much does a water heater weigh? 

In order to fully understand how heavy a water heater is, you first need to know about the factors that can impact the appliance's weight. There are three big things that will determine a water heater's weight, including:  

  • Water Heater Type
    The 2 main types of water heater are tank and tankless. Tank heaters use a large tank to store the water after it has been heated, while tankless models heat the water on demand once a hot water faucet has been turned on. Because there is no large tank necessary in tankless heaters, tankless models are the much smaller - and lighter - option. 
  • Tank Size
    If you opt for a tank water heater, another important factor in determining weight is the tank size. Water heater tanks for residential use can range anywhere from 30 gallons to 100+ gallons; the smaller the tank size, the lighter the appliance will be. This is because larger tanks require more material in order to hold more water. 
  • Empty Or Full
    Water isn’t weightless, so whether or not your water heater is empty or full plays a huge role in its weight. According to Livestrong on the weight of water, “a gallon of water weighs about 3.79 kilograms (8.35 pounds), per the USGS.”

When you do the math, the water within a full 30-gallon tank would weigh just over 250 pounds, and in a 100-gallon tank (which is more common for commercial use), it would weigh a whopping 835 pounds when full - and that doesn’t even include the weight of the tank itself.

There are also camping water heaters available but these are generally small and portable so we have not focused on these types of units.

How to Install a Tankless Hot Water Heater

How Much Does A Water Heater Weigh, Full & Empty? 

Two of the biggest questions for determining water heater weight are:  

1. How heavy is an empty hot water heater? 

2. How much does a full water heater weigh? 

Unfortunately, there’s no answer that’s set in stone for either. Whether the appliance is empty or full, the total weight depends on a few things, like the tank size, the materials used to construct the tank, and whether it utilizes gas or electricity.  

Because larger tanks require more material, these are generally much heavier when empty than smaller tanks. Then when they have been filled, they are obviously even heavier than a smaller tank due to the greater volume of water inside.  

Even though the exact weight when empty or full depends on the specific model and tank size, here’s a quick breakdown of the most common water heater sizes for homes:  


A water heater with a 30-gallon tank is quite small, so it’s not a go-to option for families or larger households. The empty weight of a 30-gallon water heater is generally about 100 pounds or less, and when full, the additional weight of the water adds about 250 pounds. 


Similar to 30-gallon water heaters, 40-gallon models are quite small, but the extra 10-gallon capacity makes them more popular for single-family homes. The empty weight of a 40-gallon water heater is generally about 120 pounds, and when full, the additional 


If a 40-gallon heater isn’t quite enough to meet your hot water needs, the next option to consider is a 50-gallon model. The empty weight of a 50-gallon water heater is generally about 160 pounds, and when full, the additional weight of the water adds about 417 pounds. 


75-gallon heaters are a go-to choice for large households. The empty weight of a 75-gallon water heater is generally about 180 pounds, and when full, the additional weight of the water adds about 585 pounds. 


Because it’s quite large and heavy, most households don’t require 80-gallon water heaters. That being said, this is a great choice for large families, duplexes that share the same heater, etc.

The empty weight of an 80-gallon water heater is generally about 200 pounds, and when full, the additional weight of the water adds about 668 pounds.   


100-gallon water heaters aren’t common for residential use, but they’re a go-to for businesses and commercial buildings. The empty weight of a 100-gallon water heater can be upwards of 300 pounds, and when full, the additional weight of the water adds about 835 pounds.   

How Much Does A Water Heater Weigh

People Also Ask (FAQs)

Is there a big difference between a 40-gallon and 50-gallon water heater? 

Yes, there’s a difference of 10 gallons! This may seem like an obvious answer, but that extra 10 gallons does add a bit of weight - not only when the heater is full, but also when it is empty. 

Just do the math. A water volume of 10 gallons weighs 83.5 pounds, so that’s an extra 83.5 pounds when the tank is at its max.  

Does a 50-gallon water heater cost more to run than a 40-gallon? 

The cost of running a water heater actually depends more on the type of heater, like whether it's tank vs tankless and gas vs electric.  

But assuming these are the same type of heater, SFGate says that “the difference in cost of running a 50-gallon heater over a 40-gallon heater is essentially insignificant.

And, in the long run, the 50-gallon heater will actually cost less to operate because the tank's less likely to run out of hot water (and bringing a tank of cold water to operating temperature takes a lot of energy).” 

How long can you shower with a 50-gallon water heater? 

This depends on the flow rate of your shower head. Some shower heads have a flow rate of 2.4 gallons per minute (GPM), while others are designed with low-flow capabilities at 1.2 GPM. 

It also depends on the water temperature when it enters your house and your current hot water settings on the appliance.  

How much should a 50-gallon water heater cost to install? 

According to a 2021 report from HomeGuide

Water heater installation costs $600 to $1,800 on average. Tankless water heaters cost $800 to $3,500 to install on average. A new hot water heater costs $300 to $2,000 for the unit alone. Labor costs to install a standard replacement water heater are $200 to $1,000 or $300 to $2,500 for a tankless.


After reading this guide on how much water heaters weigh, you should have a much better idea of the weight of your specific appliance.

The main takeaway is that water heaters can weigh a great deal, so many homeowners opt for professional installation and servicing of their heaters. 

Josh enjoys researching, testing and diving into home improvement & DIY products. He has a passion for tools, learning new skills and fixing the everyday problems that arise around the house.