A.O. Smith Water Heater Maintenance Guide

Regular maintenance prevents unexpected failures, improves efficiency, and can add years to your water heater's life. Neglecting simple tasks like flushing the tank or checking the anode rod often leads to corrosion, reduced capacity, and early replacement.

At a Glance

• Difficulty: Intermediate
• Time Required: 45–90 minutes (annual service); 15–30 minutes for quick inspections
• Frequency: Annually (core tasks); quarterly for quick visual checks
• Estimated Cost: $10–$150 DIY vs $150–$600 professional service

Routine Maintenance Schedule

Safety Warnings

Always shut off power (electric) or turn the gas control to OFF and shut gas supply (gas) before starting maintenance. Risk of electrocution or gas ignition. Relieve tank pressure slowly before opening valves. Scalding hot water and steam can cause severe burns.

Step-by-Step DIY Guide

You MUST provide at least 5 to 7 distinct steps. Do NOT group multiple different maintenance tasks into a single step. Each task must be its own dedicated Step.

Step 1: Power/Gas Shutoff

Turn off the water heater's energy source before any work. For electric units, switch off the dedicated breaker at the panel. For gas units, turn the gas control knob to OFF and shut the gas supply valve. Verify the unit is cool before proceeding.

Step 2: Inspect the Area and Exterior for Leaks

Visually inspect around the tank, fittings, and valves for water, rust, or corrosion. Check the pressure relief discharge tube and plumbing nearby. Note any active dripping or puddles—document location and severity for repair.

Step 3: Test the Temperature & Pressure (T&P) Relief Valve

Place a bucket under the T&P valve discharge tube. Lift the valve lever briefly to allow water to flow; it should discharge freely and stop when released. If it sticks, leaks afterward, or doesn't discharge, replace the valve.

Step 4: Flush the Tank to Remove Sediment

Turn off the cold-water inlet, attach a hose to the drain valve, and run it to a floor drain. Open a hot-water faucet in the house to let air in, then open the drain valve and flush until water runs clear. Close valves, remove hose, and restore fill water per manufacturer instructions.

Step 5: Inspect and Replace the Sacrificial Anode Rod (if needed)

Locate the anode rod (top of tank). Remove it with a socket wrench; it may be corroded and partially consumed. Replace the rod if it’s heavily corroded (less than 1/2" diameter or coated). Use a compatible replacement from A.O. Smith.

Step 6: Clean or Inspect the Heat Source

• For gas heaters: Remove the access panel and gently vacuum dust from the burner compartment, check the burner flame for even, blue combustion, and inspect the flue for obstructions or corrosion. If the flame is yellow or there is heavy soot, stop and call a pro. Do not attempt complex repairs on gas components if you are not certified.
• For electric heaters: Turn off breakers, remove access panels, and visually inspect heating elements and wiring for corrosion or burning. Tighten loose electrical connections and replace faulty elements as needed.

Step 7: Restore Power/Water and Check Operation

Close the drain valve, remove any hoses, open the cold-water inlet to refill the tank (leave a hot faucet open until water flows steadily to purge air), then restore power or relight the pilot/gas per the manual. Check for leaks and proper heating. Set thermostat to a safe, efficient temperature (120°F recommended).

When to Call a Pro

• You smell gas, see persistent gas odor, or suspect a gas leak
• No hot water after basic troubleshooting or repeated failure to ignite
• Continuous leaks, significant corrosion, or a failing tank (rust flakes, major puddles)
• T&P valve discharges frequently or will not seat properly
• Yellow burner flames, heavy soot, or venting/combustion issues on gas units
• Electrical burning smell, tripped breakers that resume after resetting