Highland sits at the base of the San Bernardino Mountains on the east side of the valley, and its housing stock is suburban and relatively young. The city’s neighborhoods range from the master-planned East Highlands Ranch community to newer subdivisions along Greenspot Road and Boulder Avenue, with older ranch properties scattered along Highland Avenue and the city’s western edges. Lots are typically flat with good setback depth, and the community’s quiet, residential character makes it a natural fit for backyard cottages and multigenerational living.
Detached ADUs are the strongest Highland path. The suburban lots in East Highlands Ranch and the newer subdivisions have the rear-yard depth to place a full-size detached unit up to 1,200 square feet with its own entrance and private outdoor space. On the older ranch properties along Highland Avenue, the larger parcels can carry a true backyard cottage with room to spare. For multigenerational households — an aging parent’s suite or an adult child’s home — a detached unit gives family members genuine independence on the same property.
Garage conversions and attached additions fit the denser tract homes. Converting an existing two-car garage into a one-bedroom ADU avoids new setback questions and, under state law, generally cannot be burdened with replacement parking requirements. Junior ADUs (JADUs) — compact, up-to-500-square-foot units carved from existing living space — are a low-cost entry point for family housing. State law prohibits cities from requiring owner-occupancy for standard ADUs, so most Highland ADU projects can be rented to long-term tenants without the homeowner living on site.
The City of Highland’s Planning Division reviews ADU permits, and California’s ministerial (by-right) approval process applies — a compliant project cannot be subjected to discretionary hearings. State law caps required side and rear setbacks at 4 feet. One local wrinkle worth an early check: parcels along the mountain foothills and near the canyon mouths may fall in fire-severity or flood-adjacent areas with additional building considerations, so we confirm fire-severity mapping during feasibility on properties near the base of the mountains.
Rental demand in Highland draws on the employment corridors of neighboring San Bernardino and Redlands — the medical centers, university employers, and logistics base within a short commute — plus commuters drawn by Highland’s quieter residential character. Construction notes for older stock: ranch homes on the city’s western edges may need electrical panel and sewer lateral evaluations before a second unit is designed. Whether the goal is monthly income, housing for family, or both, Highland’s suburban lots and by-right state framework make the feasibility path clear.
Ready to find out what your Highland lot can carry? ADU Cities is a Southern California ADU design-build firm — we handle feasibility, design, permits, and construction under one roof. Call 310.880.9718 for a free consultation and site evaluation. CSLB #1138550.