employees, invested heavily in Mountain House beginning in 2005, purchasing approximately 9,000 residential lots from Shea Homes. By May 2010, the $1.12 billion investment by CalPERS had been reduced to 18% of that figure: $200 million. Even though home values had dropped significantly, CalPERS determined that they would hold on to the investment, counting on a recovery of the housing market. Economic recovery An uptick in economic performance at Mountain House was noted in September 2011 by Big Builder, a trade magazine of major land and housing development published by Hanley-Wood. Acknowledging the New York Times 2008 article that branded Mountain House as the most underwater community in America, the article chronicled a grassroots commitment by residents to keep their neighborhoods looking well-kept by mowing neglected lawns of homes in foreclosure, short sales or abandoned. This community spirit helped persuade CalPERS to hold onto its Mountain House investment, despite the drawbacks of a 1994-vintage land plan, termed "out of sync with the realities of the post-housing crash world". Helping to balance the challenges of the land plan was the level of established infrastructure and homebuyers motivated by affordable pricing, proximity to job centers and traditional neighborhoods. In April 2012, Big Builder again reported on the community, noting more robust first-quarter sales, new lot offers, and flexibility for semi-finished and raw land in future development. Geography Mountain House lies on the foothills of the Diablo Range, and close to the Altamont Pass which is over in elevation. It is on the border of Alameda and Contra Costa counties. According to the United States Census Bureau, the CDP covers an area of , all of it land. The census definition of the area may not precisely correspond to local understanding of the area with the same name. The community is bisected by Mountain House Creek. Mountain House Creek originates south of the Altamont Pass and Interstate 580, flowing northeasterly along and crossing under the interstate, then along Grant Line Road to the intersection with Mountain House Road at the historic Alameda County Mountain House. The creek continues northeasterly through the residential communities of Mountain House before emptying into the Old River, a distributary of the San Joaquin River. Climate Winter (December–February) temperatures in Mountain House range from the 30s to 60s °F (-1 to 20.5 °C). Springs (March–May) in Mountain House are mild with temperatures in the 40s to 80s °F (4.4