Water Heater Basics: What Home Inspectors Check and When to Replace

The water heater is one of those home systems most people ignore until it fails. During every home inspection, we evaluate the water heater carefully.

How to Find the Age of Your Water Heater

The manufacturing date is encoded in the serial number on the label. The average lifespan of a traditional tank water heater is 8–12 years. Tankless water heaters typically last 15–20 years. A heater that is 10+ years old is always noted in our inspection reports.

What We Check During an Inspection

• Age and condition: Rust, corrosion, and mineral buildup indicate maintenance history.
• T&P valve: This safety device prevents catastrophic pressure buildup. Discharge pipe must run down, not up.
• Proper venting: Gas water heaters must vent combustion gases outside. Flue connector must slope upward toward the chimney.
• Sediment buildup: Causes the characteristic rumbling sound of an aging heater. Flushing annually extends service life.
• Clearances: Must be on a raised platform if in a garage to prevent accidental ignition of flammable vapors.

When to Budget for Replacement

• Unit is 10+ years old
• Unit is 8–10 years old with visible corrosion
• Recovery time has noticeably slowed
• Rust-colored water when running hot water only
• Persistent leaks at connections or the tank itself

Water heater replacement in Baltimore typically costs $800–$1,500 for a standard tank unit installed.