How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manfuactured and modular homes

What are the signs it's time to replace my water heater?

Monday, June 6, 2022

If you wait to replace you water heater until it fails, you could end up taking cold showers for days while waiting for a plumber. And, even worse, possible water damage to the house. 

    But when is the right time to change out your old water heater? Here’s three signs it’s prudent to do it now, along with a cluster of others that indicate that now might be the right time—or might not—to get a new water heater. 

1) Tank leakage - Drip stains down the side of the water heater and/or a puddle of water below it means it's ready for retirement.

2) Rusty outer case - Raised corrosion splotches indicate failure soon, especially around the bottom of the outer case or the pipe inlets at the top.

3) It’s old - The average water heater lasts 10 to 15 years. Some last 20, and only a few get to 30 years or more. Because water heaters can corrode deeply on the inside of the tank before any visible evidence of leakage begins to show on the outside, it’s sensible to replace an older water heater instead of waiting for it to fail. 

    When to call it quits depends on your risk tolerance, and also the location of the water heater. If it is in the garage, or other location where leakage would not do significant harm to nearby surfaces, you might wait a little longer. But a water heater inside the home can cause a lot of damage if tank failure isn’t noticed for a couple of days, and especially if it’s in a second floor closet with no catch pan and drain underneath it. 

    An ancient water heater can also make it more difficult to get or renew homeowners insurance. Most insurers will not issue a policy for a home with a water heater that is over 30 years old because of the increased risk of leakage causing a water damage claim. See our article Why is an older water heater an insurance problem? for more on this issue.

    If you are not sure how old the water heater is, look for the date of manufacture on the data plate on the side, usually near the bottom. Some manufacturers state the manufacture date clearly, but others encode it in the serial number—usually the first or second pair of numbers indicate the year, or sometimes a single letter is used. See our article How do I determine the age of my water heater? to figure out the code system your manufacturer used.

    And here’s a few problems that could be solved by a repair call, or may be severe enough to require replacement:

Inconsistent water temperature or hot water runs out quickly - This could be caused by one of the two heating elements in an electric water heater burning out, or problems with the burner of a gas water heater. If the overall condition of the heater is poor, then this is a good time for replacement.

Rusty water - Brown water could be caused by old galvanized piping or corrosion of the tank interior. If the tank is determined to be the problem, then it’s time for it to go. Replacing the sacrificial anode, which “sacrifices” itself by corroding away to stop the corrosion from attacking the tank, can add years to the life of the tank. See Why do water heaters have a sacrificial anode? for instructions.

Strange gurgling, knocking sounds - There’s a little bit of sand or debris in even the best water from a municipal or well source, and it accumulates over the years in the bottom of the water heater tank. When a heating cycle first starts, it disturbs the mat of gunk in the bottom of the tank and causes that noise you hear. It can usually be solved by draining and flushing tank. For instructions, go to Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises?. Flushing the tank every five years or so will avoid this problem. And it’s a good idea to check the sacrificial anode at the same time.

Multiple recent repairs - Similar to cars as they get older, aging water heaters start to need repairs more often, and the repairs tend to get more expensive. When the repair cost equals a big chunk of the cost of a new water heater, it may not make sense to keep it. 

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Here’s links to a collection of more blog posts about WATER HEATERS:

Are water heaters required to be raised off the floor? 

Can a Temperature and Pressure Relief (TPR or T&P) valve be mounted to discharge horizontally?

Where are gas water heaters not allowed to be installed?  

Is the minimum size water heater inlet pipe 1/2" or 3/4" according to the building code? 

Can you use a light switch for a water heater disconnect? 

How can I tell if a water heater is HUD-approved for mobile/manufactured homes?

Can you wire a 240-volt water heater with 120 volts? 

Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?  

What is required clearance for access and working space in front of an electric water heater? 

Does a water heater need a shut-off valve? 

Why should a tankless water heater have an isolator/service valve kit installed?

When was a gas water heater first required to be elevated 18 inches above a garage floor?  

Can the temperature and pressure relief (TPR) valve discharge pipe for a mobile/manufactured home water heater terminate under the home? 

What is the purpose of a thermostatic mixing valve above a water heater? 

Does a tankless gas water heater still work with no electricity during a power outage?   

What is the difference between a manufactured/mobile home water heater and a regular water heater? 

Does a tankless water heater require a pressure relief valve?

When is a water heater drain pan required?

Why is there water in my water heater drain pan?

What does it mean when a water heater Temperature/Pressure Relief (TPR) discharge pipe is "trapped"? 

Can I leave a gas water heater in place when remodeling a garage into a family room or bedroom? 

Where do I find the water heater in a mobile home?

Does a tankless water heater in an attic require a drain pan? 

Does an electric water heater require a disconnect? 

Is a catch pan and drain piping required for a replacement water heater?

What is the difference between a single element and dual element electric water heater? 

What is an FVIR water heater?

What is a dielectric union?

What's that powdery crust on the pipe connections at the water heater? 

What are the most common installation mistakes with water heater replacement?

How can I determine the age of a water heater if the serial number is missing or decoding it is impossible? 

How does a hydronic heating system work?

What is the difference between a regular water heater and a direct vent water heater? 

What is the difference between a regular water heater and a power vent water heater?

What is backdrafting at a gas water heater? 

How do I determine if a water heater is gas or electric?

What does it mean when a gas appliance (water heater, furnace, or range) has been "red tagged"?  

• What's the valve with the flip-up handle on the water heater for?

• Why is an older water heater an insurance problem?

   Visit our WATER HEATERS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles. 

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