A water heater may stop producing hot water because of a power or fuel supply issue, thermostat problem, tripped breaker, sediment buildup or failed component. Possible causes differ between gas, electric and tankless systems. Check only basic user controls described in the manufacturer's manual. Do not remove covers, handle gas connections or work on electrical components unless qualified. If you smell gas, leave the area and contact the gas utility or emergency services from a safe location. Note the heater type, approximate age and symptoms before requesting service. For water heater repair questions, call +1 (866) 569-0263 and provide your ZIP code. Ask about current service coverage and whether the requested repair or installation is available.