NAPA -- Napa County is moving along its plan to renovate the aging Health and Human Services Agency, a $76 million project that will rebuild the Old Sonoma Road campus with phased development over a span of 20 years.

The estimated cost of the constructing the first phase is $26 million, and county staff, along with the lead architect, Santa Rosa-based TLCD Architecture, presented an updated master plan and solicited public input on the project environmental impact report last week. The EIR process is expected to last until around May 2012. The cost figures are preliminary and may change pending further development with the plan, officials said.

The campus, an 8.5 acre site, is bounded by Old Sonoma Road, Walnut Avenue, Gesford Street and Pine Street. It was constructed in the early 1900s and has outlived itself and will not accommodate for the projected growth of Health Services, the county has said.

Initial planning has suggested the demolition of most of the 12 existing buildings and phased construction of about 184,000 square feet of new space, along with a total of 550 parking spaces -- more than doubling the current 242 spaces, according to the county.

As part of the planning process, the county will consider purchasing an undeveloped portion of the Napa Christian School property to the north to allow for possible expansion.

"This is a vitally important project for the residents of Napa County," said Randy Snowden, director of Health and Human Services. "We need to replace our aging and deteriorating facilities in order to continue to provided the best possible service to our clients, while also continuing to be a good neighbor and a community asset."

The current buildings are generally 55 to 75 years old and are described by the county as in "fair or poor condition."

So far, the county is focusing on aesthetics, air quality, cultural resources, greenhouse gas emissions, noise, transportation and traffic, according to Planning Director Hilary Gitelman, whose office is overseeing the EIR process.

The project calls for phased development over the next 20 years and periodic reassessments of where and when additional space may be needed.

Programs on the existing campus include the Public Health Division and Clinic; Mental Health Services; Drug and Alcohol Services; some Self-Sufficiency Services programs; Child Welfare; and Health Services Administration. The remodeled campus will include the remainder of the Self-Sufficiency programs as well as Comprehensive Services for Older Adults.

More information on the project can be found at www.countyofnapa.org/ceo/fmp