Mountain House is a census-designated place and planned community in San Joaquin County, California. An exburb of the San Francisco Bay Area, Mountain House is located 5 miles (8 km) from the City of Tracy near Interstate 205. In November 2008, the community appeared in nationwide news reports as having the highest percentage of negative equity in the U.S.—the most homes “under water”, worth less than their mortgage. In 2012, in spite of a partially outdated land plan and a lack of retail and industrial centers, Mountain House is experiencing economic recovery. In 2014 the town population was around 12,000.

Mountain House was projected to be a small full-fledged city developed over 30 year period by Trimark Communities. The community covers 4,784 acres (19.4 km2) in San Joaquin County. The town was planned for 12 distinct neighborhoods including 10 family neighborhoods and two age-restricted neighborhoods each organized around a center containing a neighborhood park, a K-8 school, and a small commercial area. Today’s Mountain House includes the established villages of Altamont, Bethany and Wicklund and the developing fourth village of Questa. At the end of 2012 approximately 3,500 homes were in Mountain House. Some 15,500 households or approximately 40,000 people are anticipated when Mountain House is fully completed. Construction at Mountain House began in 2001, but expansion stopped because of the Great Recession. Development accelerated through 2011 and 2012. Questa has six neighborhoods in various stages of completion, and three additional neighborhoods scheduled for 2013 openings. Also completed is Questa’s K-8 school and a village park. Expansion of existing neighborhoods is planned in the village of Altamont. Under construction is Mountain House High School, slated to open for the 2014-2015 academic year.[8] All schools are part of Lammersville Unified School District.