Fountain Valley is flat. The city sits on the old floodplain west of the Santa Ana River so no lot has natural fall, and water stays on a slab until the slab is shaped to move it.
A drive poured level here ponds at the garage door and against the house, and the 1960s drives, poured thin and flat by tract crews, show it after 50 winters. The panel at the door heaved and the one by the front step sank. So every slab we pour in Fountain Valley falls a quarter inch in every foot away from the house, invisible to the eye and enough to clear it within the hour, and where the lot gives the water nowhere to go, a channel drain at the low edge takes it to the street.
The ground under the slab wants the same attention. The water table across the city is shallow, since this was the artesian farmland of Talbert before the tracts came, and a subgrade that sits wet all winter turns soft under the base. We dig to firm ground, lay 4 inches of Class 2 base and compact it in two lifts, and run steel through the slab on an 18 inch grid so the panel moves as one piece if the ground under it softens.