Four fire engines and around 25 firefighters were called to a fire at a house on Rutherwick Rise in Coulsdon.
Most of the loft and roof of the end of terraced house were damaged by the fire. One man and one woman left the property before the arrival of the Brigade. There were no reports of any injuries.
The Brigade was called at 2058 and the fire was under control by 2245. Fire crews from Purley, Wallington, Croydon and Mitcham fire stations were at the scene.
The Brigade's fire investigation team believe the cause of the fire was due to an electrical event in the power switch for the shower.