Heavy rainfall and gusty winds are expected to continue today.
A low pressure system will pass west of Perth tonight before crossing the South West corner of the State during Monday morning.
"The low will produce strong to gale force winds over the ocean as it moves south and gusty winds over land, with heavy rainfall only on the southern side of the system," a Bureau of Meteorology spokesperson said.
Daily rainfall totals of 30 to 50 millimetres are forecast for the South West district with isolated falls up to 100 millimetres possible.
Since 9am on Saturday, Mandurah has recorded 29.6mm of rain and Rockingham 33.8mm.
Emergency services have answered more than 83 calls for help since 9am Friday.
The Department of Fire and Emergency Services advises that people should:
* If outside find safe shelter away from trees, power lines, storm water drains and streams.
* Close your curtains and blinds, and stay inside away from windows.
* Unplug electrical appliances and do not use land line telephones if there is lightning.
* If boating, swimming or surfing leave the water.
* Be alert and watch for hazards on the road such as fallen power lines and loose debris.
* Keep away from flooded drains, rivers, streams and waterways.
* Be careful of fallen trees, damaged buildings and debris.
* Be careful of fallen power lines. They are dangerous and should always be treated as live.
* Assess your home, car and property for damage.
* If damage has occurred take photos and contact your insurance company to organise permanent repairs.
* If your home or property has significant damage, like a badly damaged roof or flooding, call the SES on 132 500.