There has been a lot of discussion of huge homes lately after that huge mansion sold in February for $100 million. While that home set a record, many people don't know that there are in fact several homes in Los Altos Hills that fall into the same category of super mansions. What's being considered by the city is whether or not we need caps on home sizes.
Los Altos Hills allows up to 6000 square feet of living space per acre of land. This varies slightly based on the slope of the lot and the amount of space allowed to build adjusts based on a formula the city has in place. With lots of at least an acre, most people buy land in Los Altos Hills to build larger homes. Many buyers will specifically buy with the intent to build the largest possible home on whatever lot they find. The home that they want to build may include the primary residence and secondary buildings (guest homes, pool house, etc) but the overall living space is substantial. The ability to build a large estate or mansion is exactly why people buy in Los Altos Hills. Otherwise, they'll look at similar communities up and down the Peninsula.
The Town of Los Altos Hills is preparing to ask residents, once again, if caps on home size are needed. A similar survey run a few years ago showed that many didn't think a cap was necessary but if it were, the limit should be between 10,000 and 15,000 square feet. It may not be an issue because at this point there are only 6 homes with 15,000 square feet or more. There are only 16 homes with 10,000 to 14,999 square feet. Therefore the total count of huge mansions in Los Altos Hills is only 22 homes. That's not that many in the grand scheme of things. There are plans filed last year for a home with 27,000 square feet but that's the exception to the rule. Most applications are for homes 10,000 square feet or less. The "sweet spot" for luxury estates is in the 6000 to 9000 square foot range.
There are limits in nearby towns but I don't see the need in Los Altos Hills. This town has been able to attract the right people to build distinctive homes that will last for ages. I think the market keeps itself in line because very few people, even those who can afford it, will build a home as large as some mentioned in the press recently. Generally, you'll see very little need and with few lots suitable for such construction the number of possible sites to build a large mansion are limited to a reasonable number anyway.