How much does water expand in a water heater?

• <div><p>Water expands when heated and also when freezing. When water is heated, it expands by around 4%. For a full water heater, this is one of the main reasons malfunctions occur—the hot water has nowhere else to go but out. Due to the constant expansion and reduction in volume, it’s recommended (required in most places) that an expansion tank be installed. </p></div>

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Q: How big should a hot water heater expansion tank be?

• <div><p>The size needed for your expansion tank is determined by the size of your home's water heater. Expansion tanks are available in 2-gallon and 4.5-gallon sizes. A 2-gallon tank will be appropriate for water heaters up to 50 gallons. An adequately sized tank should have a volume that equals 2% to 5% of the water volume within the system. A plumber can evaluate your home's water pressure, water heater size, and other factors to provide suggestions for picking out the best expansion tank.</p></div>

Q: What size tankless water heater to replace a 50-gallon water heater?

• <div><p>A tankless water heater with a flow rate of 10 GPM should replace a conventional 50-gallon water heater. To avoid a surprise cold shower or two and to keep your energy costs in check, it's important to replace a conventional tanked water heater with the equivalent tankless water heater. Your household size and the number of hot-water-using devices you use at once can help you determine the best-size tankless water heater. </p></div>

Q: How do hot water heater expansion tanks work?

• <div><p>When the water expands in a hot water heater, it puts pressure on your hot water pipes and can cause leaks or a rupture in the hot water tank under certain conditions. Pipes or water heaters may split due to the pressure where there is a backflow preventer that prevents the hot water heater from diffusing pressure by releasing water back to the public water line.</p><p>In these scenarios, a hot water heater expansion tank provides a place for the hot water heater to relieve pressure and prevent bursts and leaks.</p></div>

Q: Can you vent a water heater outside the house?

• <div><p>Typically, only a high-efficiency water heater with an inducer fan can be vented outside the house. Otherwise, your water heater needs to be installed on the inside and vented through the roof. However, certain areas may allow a standard-efficiency water heater to be vented outside. Check your local building codes to be sure.</p></div>

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Verified Reviews for Water Heater Service pros in Backus, MN

*The Angi rating for Water Heater Service companies in Backus, MN is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Water Heater Service needs.

*The HomeAdvisor rating for Water Heater Service companies in Backus, MN is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Water Heater Service needs.

Last update on October 09, 2025

Reviewed in October 2025
Just and FYI if you are thinking of calling any company to do work on your property DO NOT call North Country Construction LLC out of Pequot Lakes MN. Owner of company if Jayden Cadias.We had him install a kitchen floor which cost $9300 and the tiles are separating. We made him aware of this,...
North Country Construction LLC
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Reviewed in July 2025
Steamboat Plumbing's owner Luke Ewert exceeded my expectations! He was incredibly helpful, friendly, and professional, taking extra time to ensure I understood my new water softener's operation, including navigating cycles and settings. He also walked me through shutting down my cabin's...
Steamboat Plumbing
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Reviewed in July 2024
We had a house fire and needed the condenser moved to the new house. They were working on it in a couple days, way sooner than expected. Very professional and good at what they do. This is my second time having them work on my ac/heating, will call them for all my needs in the future.
Lake Shore Heating and Cooling, LLC
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Reviewed in April 2022
Justin was on time and very friendly respected our home cleaned up after job was done and made sure we knew how to use the water softener before he left
Range Water Conditioning
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Reviewed in December 2021
Swenson Electric does great work. The electricians are friendly and knowledgeable. Highly recommended.
Swenson Electric
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Reviewed in September 2021
Same day service to replace water heater;Professional .friendly,and timely.
Water Heaters Now, Inc.
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Reviewed in March 2021
They work very well with the customer and help you determine what the needs you have of your pool service
Sunburst Pool Maintenance and Repair
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Reviewed in July 2018
Despite assurances from owner and son that their paint finish on cabinets would not come off even if kitchen used frequently and wiped down regularly, paint has peeled, worn thin, and chipped off even in areas that are not used. Owner repainted some of the cabinet doors first year, but did not...
Crow Wing Cabinets
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Reviewed in December 2017
Jim was very prompt, fit us in quickly to his schedule. Price for installing water softener was very reasonable compared to other quotes we had received. We would definitely use him again!
Finken, Inc.
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Find Water heater pros in Backus

Aquarius Home Services

4.6(

260

)

Solar Water Heater System - InstallTankless Water Heater - InstallTankless Water Heater - Install - For Business+6 more

Serving Backus, MN and surrounding areas

Approved

Super Service Award Winner

In business since 1987

Free estimates

Emergency services offered

"Paul did excellent work on replacing our pressure tank. Also, redid plumbing pipes by water heater."

Response time10 hrs

6 neighbors recently requested a quote

Recommended by91%of homeowners

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American Home Shield – Home Warranty

3.5(

5,688

)

Solar Water Heater System - InstallTankless Water Heater - InstallTankless Water Heater - Install - For Business+6 more

Serving Backus, MN and surrounding areas

In business since 1971

Credit card accepted

"He was very nice to talk with and repaired our washing machine. He even helped sweep the water out."

Recommended by65%of homeowners

Tankless Water Heater - InstallTankless Water Heater - Install - For BusinessTankless Water Heater - Repair+3 more

Serving Backus, MN and surrounding areas

In business since 2024

Free estimates

Credit card accepted

"Steamboat Plumbing's owner Luke Ewert exceeded my expectations! He was incredibly helpful, friendly, and professional, taking extra time to ensure I understood my new water softener's operation, including navigating cycles and settings. He also walked me through shutting down my cabin's plumbing system for the fall, allowing me to video record the process. Luke's clear explanations, patience, and personal touch made the experience seamless. His dedication to customers is impressive. I appreciated the opportunity to chat with him about his background and family, which added a nice touch to the service. I highly recommend Steamboat Plumbing and Luke Ewert for exceptional service, expertise, and customer care. I will definitely use Steamboat Plumbing again in the future!"

Response time1 day

Recommended by75%of homeowners

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Lakes Area Water Works

4.8(

)

Tankless Water Heater - InstallTankless Water Heater - Install - For BusinessTankless Water Heater - Repair+5 more

Serving Backus, MN and surrounding areas

In business since 2020

Free estimates

Credit card accepted

We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests, and make their concerns the basis of our business.

Response time1 day

Recommended by100%of homeowners

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Water Heaters questions, answered by experts

Water expands when heated and also when freezing. When water is heated, it expands by around 4%. For a full water heater, this is one of the main reasons malfunctions occur—the hot water has nowhere else to go but out. Due to the constant expansion and reduction in volume, it’s recommended (required in most places) that an expansion tank be installed.

The size needed for your expansion tank is determined by the size of your home's water heater. Expansion tanks are available in 2-gallon and 4.5-gallon sizes. A 2-gallon tank will be appropriate for water heaters up to 50 gallons. An adequately sized tank should have a volume that equals 2% to 5% of the water volume within the system. A plumber can evaluate your home's water pressure, water heater size, and other factors to provide suggestions for picking out the best expansion tank.

A tankless water heater with a flow rate of 10 GPM should replace a conventional 50-gallon water heater. To avoid a surprise cold shower or two and to keep your energy costs in check, it's important to replace a conventional tanked water heater with the equivalent tankless water heater. Your household size and the number of hot-water-using devices you use at once can help you determine the best-size tankless water heater.

When the water expands in a hot water heater, it puts pressure on your hot water pipes and can cause leaks or a rupture in the hot water tank under certain conditions. Pipes or water heaters may split due to the pressure where there is a backflow preventer that prevents the hot water heater from diffusing pressure by releasing water back to the public water line.

In these scenarios, a hot water heater expansion tank provides a place for the hot water heater to relieve pressure and prevent bursts and leaks.

Typically, only a high-efficiency water heater with an inducer fan can be vented outside the house. Otherwise, your water heater needs to be installed on the inside and vented through the roof. However, certain areas may allow a standard-efficiency water heater to be vented outside. Check your local building codes to be sure.

The Backus, MN homeowners’ guide to water heater services

From average costs to expert advice, get all the answers you need to get your job done.

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