The Bureau of Meteorology's Mount Lawley station has recorded more than 37 millimetres of rain since the storm hit, ending one of Perth's longest recorded dry spells.
The bureau's station at Swanbourne in Perth's western suburbs has recorded just over 47 millimetres.
Allen Gale from the Fire and Emergency Services Authority says it has so far received dozens of calls for calls for help, and expects plenty more as residents arrive home this evening.
He says the damage is widespread.
"A lot of traffic lights out of course and power lines across the metropolitan area," he said.
Andrew Burton from the Bureau of Meteorology says it is one of the biggest storms to hit Perth in years, with wind gusts of up to 120 kilometres an hour.
ETA: Hoyden About Town has it as 1 in 50 years. Interesting ...