Exceptional investment and special-use opportunity on an approximately 11,500 SF gated lot in Monrovia, offering multiple income, operating, and development strategies. The property features a fully renovated main residence of approximately 2,439 SF with 4 bedrooms, 4 bathrooms, plus 2 additional flexible rooms ideal for offices, administrative space, therapy rooms, or other uses. The renovation includes extensive upgrades throughout, including roof, stucco, plumbing, electrical, lighting, flooring, interior finishes, kitchen, and more. Solar is also installed. A beautifully designed detached ADU of approximately 1,000 SF offers an additional 2 bedrooms and 2 bathrooms with high ceilings, modern finishes, and excellent independent living or rental potential. Together, the main residence and ADU provide approximately 3,439 SF of living space and multiple opportunities for rental income, multigenerational occupancy, staff housing, or business operations. One of the property's strongest investment features is its reported current license for a 12-person alcohol and drug rehabilitation/recovery facility, creating a unique opportunity for qualified operators seeking an established location for behavioral health, recovery, transitional, or related residential services. Buyer to independently verify licensing, permitted use, transferability, and operational requirements. The large lot offers a long gated driveway and substantial on-site parking with room for numerous vehicles, vans, recreational vehicles, or other operational needs. A detached 2-car garage is complemented by a separate laundry area and additional restroom, adding further flexibility for residents, staff, storage, or facility operations. Another significant upside is future development potential. Based on information provided by the City, the existing detached garage may potentially be replaced with an additional residence of up to approximately 2,100 SF, creating the possibility of a third dwelling on the property. Buyer to verify all zoning, building, density, setback, permitting, and development requirements directly with the City. The property also offers expansive outdoor areas, covered patio space, a fountain, and an approximately 1,300 SF rooftop terrace, providing additional usable space for residents, tenants, clients, staff, recreation, or gatherings. Multiple investment scenarios include operating the property as a licensed recovery facility, leasing the main residence and ADU separately, creating a multigenerational or corporate housing property, combining residential and administrative uses, or pursuing future development of a third residence. With extensive renovations already completed, a separate ADU, large gated lot, substantial parking, special-use potential, and additional development possibilities, 1213 S California Avenue presents a rare opportunity for investors and operators seeking flexibility, income potential, and long-term upside in Monrovia.