Firefighters have received numerous calls relating to the floods from across the county.
Canvey is one area particularly affected but calls have also included Southend, Harlow, Aveley, Ongar, and Corringham and resources are stretched.
Incidents range from people stranded in vehicles that are stuck in flood water, cables arcing, hedgerow fires, to a house fire following a lightning strike. ECFRS responds to flood incidents where there is risk to life.
FBU members began their strike at 5pm and until 7pm calls are being covered by working crews.
Essex Police have warned that many roads are impassable and has urged motorists to avoid unnecessary journeys, slow down and drive with caution.