A house here goes down on its wet side. Where the sand under a footing sits in ground water, the load dry sand would carry is carried by nothing, and the footing follows the water table down.
Huntington Harbor was dug out of the marsh behind Sunset Beach in the early 1960s and its lots were built up from what the dredge brought out. That fill has been settling under its houses for 60 years, fastest on the canal side, where the water stands highest under the yard. The footing that goes is the one at the seawall end of the house, and the crack that shows it runs from the window nearest the water. A pier on that corner passes through fill and wet sand before it finds bearing.
Inland of the Harbor the picture changes. The slab houses on the tracts off Adams, Brookhurst and Magnolia stand on dune sand that is dry most of the year and carries them well, so a drop there has a cause under it, nearly always water we can find, a pool leaking into one corner of the yard or a lateral pulled apart at a joint. Those houses are lifted from the slab edge on brackets, the leak fixed in the same pit. Downtown, a cottage's posts go first, and they are reset on new footings.