Geography and Environment

Actual geography of the El Dorado Hills Community Region is significantly different from the corresponding Census Designated Place. The CDP is to be updated for the 2010 Census. At present the El Dorado Hills Fire Department's district covers about 2.5 times as much land area as is included in the CDP boundaries.
According to the United States Census Bureau, the CDP has a total area of 17.9 square miles (46.4 km²). In a 2005 proposal to incorporate El Dorado Hills as a city, the El Dorado Local Agency Formation Commission (LAFCo) defined different boundaries, enclosing 20,023 acres (81.0 km², or 31.3 sq mi).
In recent years El Dorado Hills has been the subject of a naturally occurring asbestos investigation after high traces of tremolite were found in the fields surrounding Oak Ridge High School. In May 2004, the Environmental Protection Agency released its findings: after taking 400 air samples throughout El Dorado Hills they found that almost every single sample had traces of asbestos fibers. El Dorado Hills citizens responded to the findings by deriding the EPA and hiring Richard Lee, an "expert" that has received more than $7 million dollars over the years for testifying on behalf of the asbestos industry. Lee had previously testified against the EPA in the Libby, Montana case. Lee declared the EPA's findings to be incorrect. There has been no clear resolution to date and citizens continue to live in El Dorado Hills despite the findings.[6]
The subsurface environment of El Dorado Hills is relatively free of groundwater and soil contamination, based upon an areawide analysis of the potential for pesticide contamination and evaluation of underground storage tanks.(Earth Metrics, 1989)