Why don't people live on the SF Bay mountains ("hills")?

June 16, 2013 11:43 PM

Driving around the Bay Area, I've always wondered: Why aren't the dry, barren hills around the bay inhabited?

If I was an old, rich person, it would seem like the top of a mountain could be a pretty awesome place to build my mansion.

Excluding the parts that are reserved public space, of course. Is it just that the mountains are so steep, that the initial cost is too high? Or some other boring reason like that?

posted by mcav to Travel & Transportation around San Francisco, CA (7 answers total)

Is it just that the mountains are so steep, that the initial cost is too high? Or some other boring reason like that?

It's just a guess, but I'd say it's something similar to that. There are hills, especially in SF, that are quite developed, so you're only noticing the undeveloped hills, which are probably larger. For the most part, it was probably easier to build on the available flattish land around the bay instead of going up into the hills, so that's what's been done. Now that the flat land is mostly occupied and the hills are attractive development targets, their development might be restricted by more enlightened zoning policies and the hills may be valued for themselves and preserved.

I don't know if there are statewide regulations in CA about it, but in my area, hillside development is strictly regulated to the point that building on a slope greater than 25% (one vertical unit for every four horizontal) is not worth the trouble. But in old parts of town, there are streets that are 25% with houses all over the place, so the regulations are a recent thing.
posted by LionIndex at 12:10 AM on June 17, 2013

In addition to the strict zoning laws mentioned by others here, many of the hills are part of open space preserves and cannot be developed.

East San Jose is expanding somewhat into the hills, and that will probably continue, because we have run out of space on flat ground.
posted by twblalock at 12:30 AM on June 17, 2013 [3 favorites]

Every time a new house or building goes up, there's an engineer somewhere out there who, long before construction began, had to survey the land and figure out what kind of foundation would be required (and this varies based on the particularities of the land in question) to prevent a slide during the rainy season, and keep the house stable during an earthquake.

A big reason that you see empty areas in the East Bay hills is that the soil/state of the bedrock/etc. are such that it would be either prohibitively expensive or outright impossible to build to code there.
posted by artemisia at 1:12 AM on June 17, 2013 [3 favorites]

Besides all the above --- too much slope, unsafe for foundations, public lands --- there's also the utilities to consider: is there enough water for a well and a safe location for a septic field? or how far away is city water & sewage and power lines?
posted by easily confused at 2:23 AM on June 17, 2013

In a previous life I was a City of San Jose planner. If you're talking about the South Bay, the city of San Jose has a strict hillside development policy. It's quite evident when you compare hillside development as you move north into Milpitas and Fremont, etc.
posted by humboldt32 at 11:44 AM on June 17, 2013

Fires and slippage caused by rain/underground hydraulics are the worst part of high hills building. Earthquakes add that extra special touch. It can be done, but doesn't it really look better without all the McMansions?
posted by BlueHorse at 1:42 PM on June 17, 2013

There are a lot of groups working to prevent over-development.
posted by radioamy at 7:47 PM on June 17, 2013