ADU Regulations in Highland, California
Everything you need to know about building an ADU in Highland — size limits, setbacks, permits, and costs.
How many ADUs are allowed in Highland?
- → 1 Detached ADU (up to 1,200 sq ft)
- → 1 Attached ADU
- → 1 Junior ADU / JADU (up to 500 sq ft)
- → Up to 8 detached ADUs
- → Interior conversions up to 25% of existing units
All California cities must follow state-law minimums. Highland follows California AB 68 and subsequent ADU laws.
Highland ADU rules & limits.
| ADUs Allowed | Up to 3 units on a single-family lot (primary home + 1 ADU + 1 JADU); up to 8 detached ADUs on multifamily lots |
|---|---|
| Max ADU Size | 1,200 sq ft |
| Setbacks | 4 ft side & rear (CA state baseline) |
| Height | 16 ft detached |
| Parking | Not required in most cases; no replacement parking for garage conversions |
| JADU Allowed | Yes — up to 500 sq ft; owner-occupancy required if JADU is present |
| Impact Fees | Waived under 750 sq ft (state law) |
| Permit Timeline | 60 days maximum (state-mandated review window) |
Parts of Highland fall within unincorporated San Bernardino County overlay zones — confirm whether your parcel is governed by Highland or San Bernardino County before submitting. We verify this during the free feasibility consultation.
Contact: Highland Planning: (909) 864-6861
What could your Highland ADU earn?
Rental estimates based on current Inland Empire market rates. Actual rents vary by condition, amenities, and local demand.
Four paths to an ADU in Highland.
From idea to reveal.
Free Feasibility Consultation
We walk your lot, check setbacks and lot coverage, and confirm what your jurisdiction will approve.
Design & Engineering
Floor plan, elevations, structural calcs, and Title 24 energy compliance — drawn for your specific lot.
Permit Submission & Approval
We submit to your city or county, manage plan-check corrections, and pay the permit fees.
Construction
Same Construction Station crew handles foundation, framing, MEP, drywall, and finish — start to keys.
Final Inspection & Move-In Ready
Final city inspection, certificate of occupancy where applicable, and two-year workmanship warranty.
Why build an ADU in Highland.
Highland's combination of larger suburban lots, semi-rural acreage on the foothill side, and proximity to San Bernardino employment makes it an underrated ADU market. Homeowners along Greenspot Road and the older Base Line corridor frequently have lots in excess of 10,000 sq ft — large enough to build a full 1,200 sq ft detached ADU without crowding the primary residence or compromising the yard. East Highlands Ranch and the newer master-planned subdivisions have tighter HOA rules to navigate, but Construction Station has worked through Highland HOA architectural review committees before. Rental demand is steady from San Bernardino County government employees, Loma Linda Medical Center commuters, and Crafton Hills College students who prefer a quieter neighborhood than central San Bernardino.
Ready to build an ADU in Highland?
We’ll walk your lot, confirm what Highland will allow, and ballpark cost before you commit to anything.
Highland ADU questions, answered.
How much does an ADU cost in Highland?
How long does it take to get an ADU permit in Highland?
Can I rent my ADU in Highland?
Do I need owner-occupancy for an ADU in Highland?
Does Construction Station build ADUs in Highland?
ADU regulations change frequently. Always verify current requirements with the Highland Planning Department at (909) 864-6861. This page was last updated May 2026.