water heater expansion tank cost

Average Cost of a Water Heater Expansion Tank Installation

To hire a plumber in your area, expect to pay an average cost of $265 to have an expansion tank added to your existing water heater. This will include the tank, all plumbing supplies, installation labor and inspection where required.

Average Do It Yourself cost


Average Contractor Installed Cost


Typical Cost Average

$145 – $350, Installed

Last Updated: Wednesday, January 12, 2022

Overview of Water Heater Expansion Tanks

Thermal expansion tanks are now required by code for most water heaters using municipal water. This is a result of new codes that require backflow valves to be installed preventing water from your home to flow back into the municipal supply. The valve creates a closed system in which pressure can build.

If you replace your water heater or sell your home, you’ll need to add one to the system. The tank will also protect your water tank, plumbing and fixtures from the increased pressure of a closed system. There’s more information below in About Water Heater Expansion Tanks.

This cost estimate page, or Costimate, covers all potential costs for DIY or hiring a professional. These include job cost factors, retail expansion tank cost and installation labor costs. Prices from a few other reliable cost estimating sites are listed. The information should allow you to make a good cost estimate of what your project price will be.

Product and Installation Supplies Cost Details

Expansion Tank Price Factors

Thermal expansion tank cost on a water heater is determined by these factors.

  • Who Installs the Tank – Most of the cost to install a water heater expansion tank is in the labor. If you can DIY, the savings will be about 75%.
  • Type of Tank Support – As simple metal or plastic strap to support the tank’s weight costs a few dollars. Steel brackets can cost 3-5 times as much as the tank.
  • Cost of the Tank – There are small cost differences in the prices of the 2-gallon to 5-gallon expansion tanks common to residential installation. Quality is also a factor in tank cost.
  • Installation Factors – When the water tank is easily accessed and there is room to work, installation charges may be lower than when, for example, the water heater is in a cramped crawlspace or utility closet.

Cost of Expansion Tank Installation Supplies

The size tank required is based on water heater capacity and the pressure of the incoming water supply line, this is especially important if you have a well pump. Most expansion tanks are less than 5 gallons, since residential water heaters range from about 30 to 100 gallons. Look for a lead-free tank rated for potable water.

Online sellers like Supply House have calculators or charts showing what size tank you’ll need.

Pro Tip: It’s always better to have a tank that is too large than one that isn’t large enough. When in doubt between two sizes, pick the larger tank.

Here are retail expansion tank and installation supply prices.

  • $35 – $70 | Residential Expansion Tanks, 2.0 to 5.0 gallons
  • $50 – $200 | Steel Tank Mounting Bracket
  • $6 – $12 | 30-foot Roll of Metal Hanging Strap
  • $15 – $25 | Pipe Cutter
  • $12 – $20 | 10” to 14” Pipe Wrench
  • $3 – $8 each | One ¾” Connector
  • $2 | Copper Tee
  • $6 – $8 | Short Section of Copper Pipe
  • $2 – $4 | Teflon PTFE Pipe Tape
  • $4 – $8 | One copper female threaded union
  • $25 – $40 | Soldering Kit, (pros prefer soldered connections to a “shark bite” connector)

About Water Heater Expansion Tanks

Here’s why you might need a thermal expansion tank.

Water expands when heated. For example, 40 gallons of water at 60F becomes about 40.6 gallons at 120F, creating significant pressure inside the water tank and pipes.

In older water systems, that extra capacity was pushed back into the municipal water system, an open system. No problem.

By the early 2000s, most cities and counties required check valves on residential water lines to prevent this. These regulations produced closed systems that gave expanding water nowhere to go. The increased pressure often damages the water tank, pipes and fixtures. One plumbing contractor says, “I have seen several cases where pipes or water heaters split due to the pressure…so the expansion tank IS necessary if you have backflow preventing devices.”

Hence, adding a water heater expansion tank became a common indoor home improvement project when connected to “city water.” If you build a new home or have an inspector in to check the installation of your new water heater, you’ll probably have to add an expansion tank to meet code.

Permits, Inspection, Related Costs and Installation Time

Permits and Inspection Cost

  • $0-$125 | In most counties, no permit is needed for the installation of an expansion tank. If the installation is part of installing a new water heater, then a permit might be required. Your local building department can let you know if a permit is required.

Related Costs and Installation Time

Hiring a licensed plumber is your best bet for having the job done correctly the first time. However, an experienced handyman might do a good job too.

Here are labor ranges for each:

  • $75 – $150 per Hour | Plumber Rates
  • $60 – $100 per Hour | Handyman Rates

This is a quick job for most pros:

  • 1-2 Hours | Time to Install a Water Heater Expansion Tank

DIY or Hire a Pro?

Installing a water heater expansion tank is moderately difficult. Here are the basic steps to help you evaluate whether to tackle it or call a pro.

First, you’ll need the tools and supplies listed in the Retail Costs above.

The expansion tank goes on the incoming supply line. Most installers place them directly above the hot water tank, so the expansion tank is horizontal. This is the easiest way to apply a metal support strap.

However, anywhere on the supply line after the water shut-off valve is OK. The expansion tank can hang vertically as long as it can be supported.

Thermal expansion tank installation step by step:

  1. Turn off the water, and open a spigot to take water pressure off the line.
  2. Turn off power to the water heater and/or shut off the gas by turning the valve to the closed position (the handle will be perpendicular to the gas line).
  3. Have a bucket handy to catch any water left in the supply line. Cut the supply line using a pipe cutter to get the cleanest cut.
  4. Install the copper Tee on the supply line, and solder it in place, if necessary.
  5. Attach the thermal expansion tank. Wrap the threads in 4-6 loops of pipe tape. Thread the connector onto the expansion tank, and attach the other end to the Tee.
  6. Use metal strapping to support the weight of the expansion tank, nailing both ends of the strap to the floor joist above.
  7. Turn on the cold water supply. If there are no leaks, turn on the water heater and gas, if it is gas fired.

Watching a pro do it, as seen in this video, will also prepare you for the project.

Photo of author

Author S Krone

A lawyer never retires. So I would just say that I am not as active as I used to be. Now I simply dedicate myself to fishing, my hobby, and my grandchildren. For Business Finance News I write about legal aspects of mortgage policies, mostly regarding the rights of policyholders. I also have articles about personal injuries.

Thank you for visiting businessfinancenews.com

Leave a Comment

Business Finance

About Us

Business Finance News is a brand oriented to business owners and dedicated to analyzing and comparing the cost and conditions of B2B procurement of goods and services through free quotes delivered by business partners.


Address 5050 Quorum Drive, (75254) Dallas TX

telephone 844-368-6072


A personal loan is a medium term loan with a fixed interest rate that is repaid in equal monthly payments and it's usually limited to 24 months. Loan offers and eligibility depend on your individual credit profile. Our lenders can help you obtain as much as $3,000 depending on the lender, your state and your financial situation.

The owner and operator of businessfinancenews.com is not a lender and is not involved into making credit decisions associated with lending or making loan offers. Instead, the website is designed only for a matching service, which enables the users contact with the lenders and third parties. The website does not charge any fees for its service, nor does it oblige any user to initiate contact with any of the lenders or third parties or accept any loan product or service offered by the lenders. All the data concerning personal loan products and the industry is presented on the website for information purposes only.

Businessfinancenews.com does not endorse any particular lender, nor does it represent or is responsible for the actions or inactions of the lenders. Businessfinancenews.com does not collect, store or has access to the information regarding the fees and charges associated with the contacting lenders and/or any loan products. Online personal loans are not available in all the states. Not all the lenders in the network can provide the loans up to $3,000. Businessfinancenews.com cannot guarantee that the user of the website will be approved by any lender or for any loan product, will be matched with a lender, or if matched, will receive a personal loan offer on the terms requested in the online form. The lenders may need to perform credit check via one or more credit bureaus, including but not limited to major credit bureaus in order to determine credit reliability and the scopes of credit products to offer. The lenders in the network may need to perform additional verifications, including but not limited to social security number, driver license number, national ID or other identification documents. The terms and scopes of loan products vary from lender to lender and can depend on numerous factors, including but not limited to the state of residence and credit standing of the applicant, as well as the terms determined by each lender individually. 


APR (Annual Percentage Rate) is the loan rate calculated for the annual term. Since businessfinancenews.com is not a lender and has no information regarding the terms and other details of personal loan products offered by lenders individually, businessfinancenews.com cannot provide the exact APR charged for any loan product offered by the lenders. The APRs greatly vary from lender to lender, state to state and depend on numerous factors, including but not limited to the credit standing of an applicant. Additional charges associated with the loan offer, including but not limited to origination fees, late payment, non-payment charges and penalties, as well as non-financial actions, such as late payment reporting and debt collection actions, may be applied by the lenders. These financial and non-financial actions have nothing to do with businessfinancenews.com, and businessfinancenews.com has no information regaining whatsoever actions may be taken by the lenders. All the financial and non-financial charges and actions are to be disclosed in any particular loan agreement in a clear and transparent manner. The APR is calculated as the annual charge and is not a financial charge for a personal loan product. 

Late Payment Implications

It is highly recommended to contact the lender if late payment is expected or considered possible. In this case, late payment fees and charges may be implied. Federal and state regulations are determined for the cases of late payment and may vary from case to case. All the details concerning the procedures and costs associated with late payment are disclosed in loan agreement and should be reviewed prior to signing any related document. 

Non-payment Implications

Financial and non-financial penalties may be implied in cases of non-payment or missed payment. Fees and other financial charges for late payment are to be disclosed in loan agreement. Additional actions related to non-payment, such as renewals, may be implied upon given consent. The terms of renewal are to be disclosed in each loan agreement individually. Additional charges and fees associated with renewal may be applied. 

Debt collection practices and other related procedures may be performed. All the actions related to these practices are adjusted to Fair Debt Collection Practices Act regulations and other applicable federal and state laws in order to protect consumers from unfair lending and negative borrowing experience. The majority of lenders do not refer to outside collection agencies and attempt to collect the debt via in-house means. 

Non-payment and late payment may have negative impact on the borrowers’ credit standing and downgrade their credit scores, as the lenders may report delinquency to credit bureaus, including but not limited to Equifax, Transunion, and Experian. In this case the results of non-payment and late payment may be recorded and remain in credit reports for the determined amount of time.