To refill a water heater, first shut off the power and gas supply. Relieve pressure by opening the relief valve or drain valve. Open the cold water inlet valve and slowly add water until the pressure gauge reads between 40-80 PSI. Check for leaks and restore power once filled. Regular refills prevent sediment buildup, which reduces efficiency and risks overflow.

Sediment accumulation from hard water is a leading cause of water heater failure. The U.S. Department of Energy reports that sediment can reduce heating efficiency by up to 15%, increasing energy costs. A 2021 study by the American Water Works Association found that 60% of water heaters fail prematurely due to unaddressed sediment. Refilling maintains optimal internal pressure, protecting the tank from stress cracks. Additionally, proper water levels prevent dry burning of the heating element, a common cause of $500-$1,500 repair costs. The U.S. Consumer Product Safety Commission advises annual refills to extend tank lifespan, which typically lasts 10-15 years when maintained. Neglecting refills can lead to water damage, as excess sediment may force water into surrounding structures during overpressure events. Energy Star estimates that sediment-clogged heaters waste $100-$200 annually in excess energy use. By following refill protocols, homeowners can avoid costly repairs and ensure safe, efficient hot water operation.