Welcome to 4210 Rio Hondo Ave, Rosemead - a rare gated property offering versatility, modern upgrades, and exceptional income potential. Situated in a quiet, suburban-feel neighborhood, this single-story Cape Cod-style residence features 3 bedrooms and 1 bathroom across approximately 1,399 sq ft of living space. A remote-controlled front gate provides privacy and security, with an additional gated entrance along the easement driveway offering convenient rear access. Inside, the home showcases a spacious living room with a quartz-faced fireplace and recessed lighting, creating a warm and inviting setting. The adjoining dining area flows into a galley-style kitchen featuring newer granite countertops, stainless steel sink, tile backsplash, dark cabinetry, and stainless steel appliances. The bathroom has been updated with newer tile flooring, granite vanity, updated sink, tub, tile wainscot, toilet, light fixture, and mirror. Additional improvements throughout the home include updated flooring, interior and exterior paint, dual-pane windows, window coverings, light fixtures, water heater, and roof. The front and backyard have been well maintained, offering enjoyable outdoor space. A unique highlight is the large walk-out basement, providing excellent storage or potential for future use. The property also includes a paid-off solar system (approx. $45,000 value per owner), delivering long-term energy savings. Adding tremendous value is the newly constructed detached ADU (completed July 30, 2025), offering 3 bedrooms, 2 bathrooms, and approximately 1,197 sq ft, plus an attached two-car garage (approx. 460 sq ft). The ADU has its own separate mailing address (4210 Rio Hondo Ave, with the main house now addressed as 4208) and features separate utility meters for water, gas, and electricity, making it ideal for rental income, multi-generational living, or extended guest use. Located in the desirable northern portion of Rosemead, the neighborhood is primarily composed of well-established single-family homes. Enjoy convenient access to schools, parks, shopping, dining, medical facilities, public transportation, and major freeways - all within a few miles. An exceptional opportunity to own a fully upgraded property with a brand-new ADU and strong income potential - perfect for both homeowners and investors.