How to Tell If Your Water Heater Is Going Out

A West Tennessee homeowner’s guide to the warning signs, how long a tank lasts, and when replacement makes more sense than a repair.

Most water heaters give you warning before they fail completely. The clearest signs are water that no longer gets hot or runs out quickly, rusty or discolored hot water, popping or rumbling from the tank, water pooling around the base, or a unit that is more than ten years old. If you are seeing one or more of these, the water heater is likely near the end of its life and should be inspected.

In this guide: what each sign means, how long a tank water heater typically lasts, and how to decide between a repair and a replacement.

Six signs your water heater is failing

Hot water runs out faster than it used to

As sediment collects at the bottom of the tank, it takes up space that used to hold water and forces the burner to work harder. Showers that turn cold early are often the first thing homeowners notice.

The water looks rusty or has a metallic smell

Discolored hot water usually points to corrosion inside the tank or a failing anode rod. Once the tank itself begins to rust, replacement is the only reliable fix.

Popping, rumbling, or knocking from the tank

That sound is water bubbling through hardened sediment. It signals the tank is losing efficiency and working under more stress than it was built for.

Water pooling around the base of the tank

Moisture or standing water at the base usually means the tank has cracked. A leaking tank cannot be repaired and needs to be replaced.

Water temperature keeps swinging hot and cold

Inconsistent temperatures often trace back to a failing thermostat or heating element. On a newer unit this is repairable, but on an older one it tends to be one of several parts wearing out.

The unit is more than ten years old

Most tank water heaters last about ten years. Past that point repairs add up quickly, and replacing the unit is usually the better investment.

How long a should a water heater last?

A conventional tank water heater should last about ten years, but that number assumes the unit is maintained. Two items decide whether it gets there, and the water source has little to do with it.

Anode rod, every two years

It corrodes so the tank does not. Inspected and replaced on schedule, it protects the tank from the inside.

Tank flush, once a year

Clears the sediment that settles at the bottom. The same schedule applies on well water or city water.

What affects the cost of replacement?

For a like-for-like replacement in West Tennessee, a 40 or 50 gallon electric unit typically runs $1,600 to $2,000, and a comparable gas unit typically runs $1,800 to $2,200. These are standard installs in an accessible location.

Electric, 40 to 50 gallon

$1,600 to $2,000

Standard like-for-like swap in an accessible location.

Gas, comparable size

$1,800 to $2,200

Standard like-for-like swap in an accessible location.

Repair or replace?

Repair makes sense when the water heater is not showing signs of deterioration. As a general rule, a unit six years old or younger is worth repairing, because at that age the tank itself is usually still sound and the problem is a single component.

The most common call we get is a home running out of hot water faster than it used to. On an electric unit, that is typically a failing thermostat or heating element, not the tank. Replacing both thermostats and both elements usually solves the problem and keeps the water heater running for several more years.

Electric thermostat and element repair

$450

Both thermostats and both elements, tank flush included.

Gas valve and burner repair

Gas valves and burner replacements start at $500

Varies with what needs to be replaced.

Location is the biggest variable. A lowboy in a crawlspace or a tank in an attic is harder to reach and takes longer to install safely, which adds to the job. We look at the unit, its location, and the existing connections first, then give a firm price before any work starts.

If your water heater is past the six-year mark and showing more than one of these signs, replacement is usually the more economical choice over repeated repairs. See what a new unit involves on our water heater installation, repair, and replacement page.