A 10-unit apartment complex a mile north of downtown Fairfax will soon be owned and managed by the San Geronimo Valley Affordable Housing Association. The association plans to close on the of $2.65 million purchase in April with the help of grant monies, including $500,000 from the county awarded by supervisors last month. Another grant for the same amount from the Marin Community Foundation is pending, and the association has $75,000 from the nonprofit Tamalpais Pacific for rehabilitation. The complex, currently privately owned and rented at below-market rates, has six two-bedroom units and four one-bedroom units. Leelee Thomas, a planning manager with the county’s Community Development Agency, first identified the opportunity to help preserve the housing and presented the association with the possibility of a purchase last year. It’s an example of naturally occurring affordable housing, Ms. Thomas said, with a long-term relationship between the tenants and owners who kept rents low. Rents will not change for existing tenants, and rates for any new tenants will be based on standards set by the Department of Housing and Urban Development. The valley housing association already manages 26 units on two properties, including a mobile home park in Forest Knolls and three shared units for seniors in San Geronimo. Suzanne Sadowsky, the chair of the board, said although the property is on the other side of White’s Hill, “it was close enough, and it was an opportunity we couldn’t let go in terms of our mission.” She added, “There’s a lot of crossover with Fairfax as far as income and need, and also for events and activities—with people coming to the community center here for activities—and of course we go over there at least a few times a week.” The association will continue to fundraise. “We hope that both the residents of West Marin and in Fairfax will agree it’s a wonderful project, and will step up and help support the project,” Ms. Sadowsky said. The county’s financial contribution came out of the affordable housing fund, which is fed by county development fees as well as the general fund and is specifically earmarked to increase the affordable housing stock. Ms. Thomas said the property helps the county meet the goal set by a 2019 voluntary compliance agreement with HUD to develop or purchase 100 new rental units within three years. The Fairfax purchase marks the third time since 2016 that the county has contributed funds toward the development or preservation of affordable housing complexes in Fairfax; today, there are 27 units at the Piper Court Apartments and, beginning this summer, there will be 53 at Victory Village. Mark Switzer, the project development coordinator for the valley housing association, said the purchase could provide a model for other homeowners hoping to sell. In this case, the owner is a recent widow who owned the property with her late partner. “She took the extraordinary step of wanting to meet with a housing agency that could potentially buy the property and continue to manage it where the tenants wouldn’t be displaced and the rents jacked up. And so that’s what we did,” Mr. Switzer said.