The headline after the next major Bay Area earthquake may be: "Housing Losses Staggering Due to Failure to Retrofit Apartments and Condos with Known Earthquake Risk." Of the 160,000 housing units ABAG forecasts will uninhabitable in a major earthquake, most will be the result of the collapse of apartment buildings with parking or commercial space on all or part of the first floor. The collapse of the parking areas of types of apartments and condos occurred in the 1971 San Fernando earthquake, the 1989 Loma Prieta earthquake, and the 1994 Northridge earthquake.

San Francisco's Building Department determined that the collapse of these apartments is likely to be responsible for about half of all of the damage to privately-owned buildings in that city in a magnitude 7.2 San Andreas earthquake. The Earthquake Engineering Research Institute's Northern California Chapter estimates that there are approximately 15,000 of these buildings in the nine-county Bay Area. Based on city and county data, there are 2,630 of these buildings in Santa Clara County housing about 90,000 people and 5,700 soft story buildings in San Francisco housing about 180,000 people.