5 Signs Your Water Heater Is Going Out and Needs Replacement

Is your water heater on its last leg?

Many homeowners overlook the subtle signs of a failing water heater until it’s too late, leaving them with cold showers and unexpected repair bills.

In this guide, we’ll walk you through the 5 signs your water heater is going out so you can act before a complete breakdown. From strange noises to inconsistent water temperatures, we’ll cover everything you need to know to spot the warning signals early.

You will find answers to questions such as: How do you know a water heater is going bad? When should I replace it? Why is my water heater leaking, not working, or performing improperly?

By the end, you’ll be equipped to make informed decisions about repairs or replacements, saving you time, money, and frustration. Don’t let a failing water heater catch you off guard—read on to learn what to watch for!

Typical Signs Your Water Heater Is Going Out and About to Fail

Is Your Water Heater Going Bad Because It Is Too Old?

Check the age of your water heater. If it is more than 10 years old, consider replacing it. According to experts, most water tank heater breakdowns begin to happen at 10+ years of age.

If you are seeing a reduction in hot water supply, decreased energy efficiency, or increased energy costs, you might have a unit that is simply too old and needs replacement.

This is how you can check the age of your water heater and eventually prevent it from going bad:

Find the manufacturer’s sticker or rating plate located on top of the unit or near other stickers (e.g., warning labels or energy guide). It lists important info such as the serial number, model, fuel type, manufacture date, company name, capacity, BTU or wattage, etc.

Look for the serial number because some numbers or letters indicate the year the water heater was built. Since the serial number format varies by manufacturer, here are examples from three popular brands:

• AO Smith serial number: 1803***** – Built in 2018 (18 is the year), week 3 (03 is the week).
• Rheem serial number: 1015***** – Built in October (10 = month), 2015 (15 = year).
• Bradford White serial number: MA***** – Built in January (A = month), 2015 (M = year).

For Bradford White:

• Months: A = January, B = February, … M = December.
• Years: A = 1984/2004, B = 1985/2005, … T = 1999/2019, W = 2000, X = 2001, Y = 2002, Z = 2003.
  (The above applies to subsidiary companies as well.)

You can also find the manufacture date in the unit’s manual or by checking online or on the manufacturer’s site.

Most tank-type water heaters have a 6-year warranty and last between 10 to 15 years. Some last more; some less.

A water heater’s life expectancy depends on many factors, including the quality of installation, maintenance, water quality, and usage.

If your tank-type water heater is more than 10 years old, you could expect components to fail, reduced efficiency, and longer heating times.

If your water heater is old and you want to avoid expensive future breakdowns and significant property damage, start looking for a new high-efficiency unit. Better models come with 10 and 12-year warranties.

If you prefer on-demand heating and a continuous supply of hot water, consider tankless units. Tankless water heaters last much longer—over 20 years—and better models have 15-year warranties. The longest warranties are on Rinnai and Takagi models.

Corrosion and Rusty Water Can Lead to Water Heater Failure

The first signs of corrosion in a water heater often appear as rust on its exterior, which can eventually lead to leaks, or as rusty, discolored hot water caused by internal damage.

Most tank-type water heaters are designed with a glass liner and an anode rod to protect against corrosion, but these safeguards deteriorate over time, leaving the tank vulnerable. Cracks in the glass liner from manufacturing flaws, thermal stress, or chemical reactions allow water to reach the metal tank, resulting in rust.

Here are some tips to help your water heater last longer:

Tip 1: Inspect the anode rod annually (or as recommended by the manufacturer) and replace it if necessary to prevent corrosion.

To check for internal corrosion, attach a garden hose to the drain valve at the bottom of the heater and drain a few gallons of water. If the water appears rusty or has a metallic taste, it’s a sign that corrosion may have already started.

Tip 2: Drain and flush the water heater yearly to remove mineral deposits and sediment buildup that can contribute to internal damage.

Tip 3: Prevent corrosion by using dielectric fittings made of galvanized steel with inner plastic tubing, which can help reduce the risk of electrical corrosion between metal components.

Once corrosion sets in, it spreads quickly and can lead to leaks or complete tank failure. While some components may be replaceable, addressing corrosion usually involves replacing the entire water heater to avoid further damage and costly repairs. Proceed with caution and consider replacing the water heater if corrosion is widespread.

Leaks That Cannot Be Fixed

This refers to leaks that are difficult or impossible to fix, not minor drips from plumbing or loose connections.

The first sign of a leak is water pooling under the heater. Major leaks can cause property damage, especially if the unit is in the attic or near living spaces.

If your water heater leaks due to corrosion or mechanical stress, replace it immediately. When fractures first form, they are tiny, but over time, exposure to thermal stress makes the leaks worse.

Fix leaks promptly to prevent damage, mold, mildew, and health risks.

Bulging Water Heater and Excessive Internal Pressure

A bulging water heater is a serious problem caused by excessive pressure inside the tank or blockage.

Common symptoms include:

• Deformations (e.g., bent nipples or dislocated flue pipes).
• Leaks.

A deformed water heater cannot be repaired and must be replaced. Prevent this by installing the unit properly, including an expansion tank.

If left untreated, the water heater may burst.

Heavy Sediment Buildup and Strange Noises

If your water heater is underperforming, making strange noises (rumbling, knocking, popping), or taking too long to heat water, inspect it for sediment buildup.

Hard water causes mineral deposits to form at the bottom of the tank, insulating the heat source from the water and reducing efficiency, potentially causing your water heater to go bad.

To prevent sediment buildup: Flush the water heater regularly, as recommended by manufacturers and experts.

New Water Heater Installation Prices

When the time comes to replace your unit, start searching for a new system and gathering quotes.

Installation costs vary by region and contractor, but here are some numbers (2022) for your reference:

• Tank-type: $150–$600.
• Tankless: $400–$1,500.

According to HomeAdvisor.com, the average replacement cost is $1,168, with a typical range of $805 to $1,554. A cost calculator is available on their site for city-specific pricing.

Conclusion

Every water heater will experience issues over time, and many factors contribute to its eventual failure. While we’ve covered some of the most common causes, it’s important to remember that regular maintenance is key to prolonging your unit’s lifespan. If you notice signs that your water heater is going out and beyond repair, as discussed, it’s best to reach out to a licensed technician for a replacement. Taking action early can save you from further inconvenience and prevent costly damage down the line.