Sonora will need to add 405 new residential units by 2008 to meet its projected housing needs, according to a just-released portion of the city's general plan.

The plan's housing element also details ways to increase the city's stock of affordable housing through new construction and the rehabilitation of older, dilapidated homes.

With the sharp rise of home and rental prices in recent years, housing has become one of Sonora's most prominent issues. The plan's housing portion, still in draft form, is intended to give city leaders long-term guidance on how new housing in Sonora should be developed.

"It is the road map for how the city will provide housing," said Amy Augustine, a planning consultant for the city.

Of the 405 new units, 54 should be affordable for households with "very low" annual incomes defined by the state as less than $23,900 and another 68 for "low income" households, earning between $23,901 and $38,240 annually, according to the plan.

The remaining 283 units would house people with "moderate" or "above moderate" incomes.

The housing projections come from the Central Sierra Planning Council's Regional Housing Needs Assessment. They are are based on statistics like city income levels and population predictions, Augustine said.

By 2008, Sonora's population is expected to grow to more than 5,100 people, up from 4,600 this year, according to the general plan. Sonora had an estimated 2,261 housing units within its limits at the start of 2003, California Department of Finance figures show.

Compared to the rest of Tuolumne County, Sonora has an over-concentration of very-low-income households, Augustine said.

The housing allocation projection is "intended to encourage a more equitable distribution of housing between the city and county for very-low-income households," according to the plan.

Although the general plan's housing element provides detailed figures, city officials treat it as a guide rather than a series of projections that need to be met exactly, said City Administrator Greg Applegate.