Restoring Heating Systems After a Flood Assessing Damage And General Clean-Up

Any heating system exposed to flooding should be professionally inspected, cleaned and reconditioned before reuse. Floodwater may have damaged heating equipment and undermined chimneys. If chimney cracks or leaks go unrepaired, your family is at risk of fire or carbon-monoxide poisoning.

Ask the service person if there is anything you can do to help before his or her arrival. Usually this will include turning off fuel and power to flooded units as a safety measure, and removing mud and debris from the furnace housing and inside the chimney. Leave things like inspection of oil storage tanks and cleaning of motors, blowers and other flooded parts to the professional. Flood insurance and federal disaster assistance programs usually will help replace flooded gas and oil appliances, including furnaces.


In general, any flooded parts should be professionally inspected and cleaned before turning the system back on. Check your owner's manual if you are unfamiliar with the system.

  • If your furnace was flooded to the level of the burners, turn off the valve on the pipe leading to it. If burners were hot when flooded, parts may have cracked.
  • Modern furnaces also have an electrical switch for blowers. Turn this off as well if any furnace parts were flooded.
  • Have the storage tank inspected by an experienced person to make sure water and dirt have not entered.
  • Have the electric motor, burners, blowers, fuel pump and gears cleaned and reconditioned by an expert. Flooded fuel filters should be replaced.
  • Be certain that the fan motor, electric ignition systems and wiring are completely clean and dry before you turn on the electricity.
  • If you have a hot water system, clean the fins on baseboard radiators. Clean any wall radiators.
  • Some natural gas systems may have a valve to the pilot gas line, in addition to the main fuel valve. Turn both off if this is the case.
  • Have a service person:

a) Check to see if water leaked into the controls or pressure regulator.
b) Clean and recondition all flooded equipment, including burner elements, electric controls and regulators.
c) Replace severely flooded electric blower motors.

  • If you smell natural gas - which has a distinctive, putrid odor - leave your home and contact your utility company or a service person. Do not use open flames in the area.

Electric heating systems are part of electrical wiring system clean-up. Many local codes require that a licensed electrician do the work, or that a municipal inspector check the system before you turn the power back on.

If power isn't shut off to a flooded furnace system, shut the main switch off at the meter or remove the fuse to the furnace. (When touching switches, stand on a dry board and use rubber gloves or a dry stick to pull handles.)

Clean mud and debris from electric baseboard heating fixtures, being careful not to damage heating equipment. Have a professional handle cleaning and reconditioning of all working parts.


A cracked, clogged or leaky chimney can cause fires or carbon monoxide poisoning. Be sure you check your chimney for dirt, debris and leaks before lighting the furnace or a fire. If flood damage has occurred, have a mason do an inspection and make repairs.

  • Most chimneys have a foundation in the ground. If the chimney looks like it has settled or tilted, examine the footing to see whether it has been undermined.
  • Have the chimney rebuilt if it has settled badly or is broken where it passes through floors or roof.
  • If mortar in the joints between bricks has disintegrated, have a mason rejoint the chimney with cement.

Additional resources:

Your county family living agent, your local emergency government office, the American Red Cross, the Federal Emergency Management Agency

Related publications:

"Repairing Your Flooded Home," American Red Cross/Federal Emergency Management Agency, 1992.

Pamphlets on heating systems from your local utility company.

Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More