9 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 9 signs your water heater is going out so you can act before a complete breakdown. From odd noises to fluctuating water temperatures, we’ll break down the red flags you need to watch for.

Plus, we’ll share practical tips to help you decide when it’s time to replace your water heater—saving you from unexpected cold showers, expensive repairs, and even potential water damage.

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 What to Do About It)

Here, you will identify key signs indicating when to replace a water heater, covering factors such as age, rust, unusual noises, leaks, insufficient hot water, frequent repairs, rising energy bills, structural deformations, and the effects of flooding.

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

If your water heater is over 10 years old, it’s likely nearing the end of its lifespan. Most tank-style water heaters start showing signs of failure after a decade, such as reduced hot water supply, lower energy efficiency, or higher utility bills.

To check the age of your unit, follow these steps:

• Locate the Manufacturer’s Sticker: Look for the rating plate or sticker on the unit, usually near the top. It will list details like the serial number, model, fuel type, and manufacture date.
• Decode the Serial Number: The serial number often includes the manufacture date, but the format varies by brand. Here’s how to decode it for three popular manufacturers:
  • AO Smith: Example serial number 1803**** means the unit was built in 2018 (18 = year), week 3 (03 = week).
  • Rheem: Example serial number 1015**** means October (10 = month) 2015 (15 = year).
  • Bradford White: Example serial number MA**** means January (A = month) 2015 (M = year).
    • 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.

If you’re unsure, check the unit’s manual or visit the manufacturer’s website for more details.

How Long Do Water Heaters Last?

Most tank-style water heaters come with a 6-year warranty and typically last 10 to 15 years. However, their lifespan depends on several factors, including the quality of installation, how well they’re maintained, the quality of your water, and how heavily they’re used. Once your unit reaches the 10-year mark, you’ll likely notice signs of wear and tear—components may start failing, efficiency can drop, and heating times often increase.

If you’re looking for a longer-lasting solution, consider upgrading to a tankless water heater. These units are designed to provide on-demand heating and, with proper maintenance, can last over 20 years. Top brands like Rinnai and Takagi even offer 15-year warranties on their premium models, making them a reliable and cost-effective choice for the long term.

Corrosion and Rusty Water Can Lead to Water Heater Failure

The first signs of corrosion in a water heater often show up as rust on the exterior or discolored, rusty hot water caused by internal damage. While these issues might seem minor at first, they can quickly escalate into leaks or even complete system failure if left unchecked.

Most tank-style water heaters are built with protective features like a glass liner and an anode rod to combat corrosion. However, over time, these safeguards wear down, leaving the tank exposed. Cracks in the glass liner—caused by manufacturing flaws, thermal stress, or chemical reactions—can allow water to seep into the metal tank, leading to rust and eventual failure.

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 it’s worn out. This simple step can significantly slow down corrosion. To check for internal corrosion, attach a garden hose to the drain valve at the bottom of the unit and drain a few gallons of water. If the water looks rusty or has a metallic taste, corrosion may already be underway.

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

Not all leaks are created equal. While minor drips from plumbing or loose connections can often be repaired, some leaks are difficult or impossible to fix. These are typically caused by serious issues like cracks or fractures in the tank itself.

The first sign of a major leak is usually water pooling under the water heater. If the unit is located in an attic or near living spaces, a large leak can lead to significant property damage. For example, a fractured or cracked tank can release a substantial amount of water, causing harm to floors, walls, and belongings.

Leaks often occur due to corrosion or mechanical stress over time. Initially, fractures may be small, but constant exposure to thermal stress can cause them to worsen. If you notice a leak caused by these issues, it’s crucial to replace the water heater immediately.

Ignoring leaks can lead to more than just water damage. Over time, standing water can promote the growth of mold and mildew, which pose health risks to you and your family. To avoid these problems, address leaks as soon as they appear and consider replacing your water heater if the damage is beyond repair.

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.

Insufficient Hot Water

If you’re finding that your hot water supply is not as robust as it used to be, the water heater might be losing its efficiency. This could be due to sediment buildup, aging elements, or other wear and tear that affect its performance.

For example, if your showers are getting shorter or you need to wait longer between uses, it’s a sign that the device isn’t performing as it should. When to replace a water heater is often driven by this decline in performance, as a new unit can restore the consistent and reliable hot water supply you’re used to.

Frequent Repairs

When the cost of repairs starts to add up, it might be more economical to replace the unit altogether. Frequent issues are a strong indicator that the water heater is on its last legs.

For instance, if you’ve had to call a technician multiple times in the past year for various problems, the cumulative cost of repairs could approach the cost of a new unit. Instead of pouring money into an aging and failing system, investing in a new, more efficient model can provide peace of mind and long-term savings.

Rising Energy Bills

Aging water heaters can become less efficient, leading to increased energy consumption and higher utility bills. If you notice a significant spike in your energy costs, your heater could be the culprit. Newer models are designed to be more energy-efficient, which can save you money in the long run. The right timing for replacement is often influenced by this economic factor, as the initial investment in a new unit can be offset by lower operating costs over time.

Flooding

If your basement or the area around your water heater has been flooded and the water heater has been submerged for any length of time, it is crucial to consider replacing it. Flooding can damage the internal components of the water heater, including the insulation and electrical parts, making it unsafe to operate. Even if the heater seems to be working fine after drying out, hidden damage could lead to future failures.

New Water Heater Installation Prices

When the time comes to replace your gas or electric water heater, 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. Knowing when to replace a water heater can save you from unexpected inconveniences and potential damage to your home. Keep an eye on the age, performance, and any unusual signs from your heating device.

Proactively replacing it before a catastrophic failure can ensure you always have a reliable supply of hot water and can prevent costly repairs and water damage.

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.