Preventive maintenance for a hot water heater ensures optimal performance and longevity. Start by regularly inspecting the tank for signs of leaks, rust, or corrosion. Check the temperature setting on the thermostat, ideally around 120°F, to prevent overheating and excessive energy use. Flush the tank annually to remove sediment buildup, which can hinder heating efficiency and cause damage over time. Inspect the anode rod every 1-3 years and replace it if it’s corroded to protect the tank from rust. Ensure proper ventilation, clean the burner if it’s a gas heater, and check the pressure relief valve for proper operation to prevent dangerous pressure buildup.