About 538 Plumosa Ave
The Mainsail Horizons of Vista Project
RECORD ID: PDS2017-MPA-17-012; APN 217-131-58
The Mainsail Horizons of Vista project (PDS2017-MPA-17-012) consists of an application for a Major Use
Permit to allow the construction of an Assisted Living and Memory Care facility on an approximately 2.6-
acre vacant property. The site supports two more-or-less discrete plant communities or habitats: Non-native
Grassland and Disturbed/Developed habitat. The project as proposed will impact biological resources,
resulting in a need for mitigation. Mitigation must take place offsite in a County-approved location due to
full site use for development purposes. In addition, an avian nesting survey and/or seasonal restrictions on
any future site development are recommended to ensure project consistency with the Migratory Bird Treaty
Act and the California Fish and Game Code.
The Mainsail Horizons of Vista project is an application to allow the development of an approximately 2.6-
acre parcel (APN 217-131-58) under a Major Use Permit (MUP) allowing the construction of an Assisted
Living and Memory Care facility. As designed, the facility will support a 59,148 square-foot 4-story building
along with parking spaces, a swimming pool, landscaping, other improvements and associated
infrastructure. The 2.6-acre project site is located southwest of State Route 78 and fronting Plumosa Avenue
on unincorporated County lands between the Cities of Vista and San Marcos.
