Rain barrels with rain chains have been installed in two areas at this home to capture and slow down the water from non-pervious surfaces like the roof. Due to the hillside topography, the runoff from over 3000 sq ft of roof would create erosion and runoff into the street without some mechanism to slow the water down.
The irrigation controller and rain sensor are only used for the lawn; there is no other irrigation on the property. The lawn is only 512 sq. ft. which is less than 10% of the garden area.
Drought tolerant aeoniums growing on the hillside and stabilizing the slope - no irrigation