It sits in a closet or basement, silently working day in and day out to provide the hot water that is central to modern life. Your water heater is one of the hardest-working appliances in your home, but because it's out of sight, it's often out of mind—until the day you're greeted with an ice-cold shower or, worse, a flooded floor.

A water heater doesn't last forever, and a catastrophic tank failure is one of the most damaging and expensive plumbing emergencies a homeowner can face. The key is to recognize the warning signs that your unit is nearing the end of its life *before* it fails. Here are the top five signs that it’s time to start budgeting for a replacement.

Like all appliances, water heaters have a finite lifespan. Knowing the age of your unit is the most important factor in deciding whether to repair or replace it.

How to Find the Age: Look for the manufacturer's sticker on the side of the tank. The serial number usually contains the manufacturing date. Often, the first four digits represent the month and year (e.g., a serial number starting with "0515" was likely made in May 2015). If you can't decipher it, a quick search online for the brand and "how to read serial number" will give you the answer.

If you turn on a hot water tap and the water comes out with a brownish, rusty tint, you have a serious problem.

The Cause: This is a tell-tale sign that the inside of your water heater's steel tank is corroding. While all tanks have an internal "anode rod" designed to sacrifice itself to prevent rust, this rod gets used up over time. Once it's gone, the water begins to corrode the tank itself.

The Critical Test: To confirm the issue is the water heater and not your pipes, check the cold water. If the cold water runs clear, but the hot water is rusty, the problem is almost certainly inside your water heater tank.

The Urgency: A corroding tank will eventually fail and leak. This isn't a matter of if, but when.

As a water heater ages, sediment (minerals from the water like calcium and magnesium) settles at the bottom of the tank. Over time, this layer of sediment gets thicker and harder.

The Cause of the Noise: The noise you hear is water getting trapped underneath this layer of hardened sediment. As the burner or heating element heats the water, it boils and tries to escape, causing rumbling, popping, or banging sounds as it pushes through the sediment layer.

The Consequences: This process has two negative effects. First, it makes your water heater far less efficient, increasing your energy bills. Second, it causes the steel tank to become brittle and stressed, accelerating its failure.

This is the most urgent and obvious sign that your water heater is failing.

The Cause: While small drips can sometimes come from fittings or the temperature and pressure (T&P) relief valve, any water pooling at the base of the tank itself almost always indicates a fracture in the internal tank. The constant heating and cooling cycle causes the steel to expand and contract, and eventually, small cracks can form.

What to Do: A leak from the tank itself is not repairable. It is a clear signal that the unit needs to be replaced immediately to prevent a major flood. If you see water, it's time to call a plumber.

If your unit is struggling to produce enough hot water, or if you're getting lukewarm water instead of hot, it's a clear sign of a problem.

Repair or Replace?: This is a gray area. Sometimes, the issue is a simple, repairable component, like a faulty thermostat or a burned-out heating element. However, if your water heater is already over 10 years old, investing several hundred dollars to repair a single component might not be wise. The failure of one part is often a sign that other parts are also nearing the end of their life. In an older unit, putting that repair money towards a new, more efficient replacement is often the more cost-effective long-term decision.

Don't wait for a cold shower or a flooded basement. By paying attention to these signs, you can replace your water heater on your own terms, saving you from the stress and expense of an emergency replacement.