ADU Checklist — Add a Rental Unit to Your Property
Is your Siskiyou County property ready for an Accessory Dwelling Unit? Use this checklist to find out.
What Is an ADU?
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a single-family residential lot. California law (AB 68, SB 13) has made it easier than ever to add ADUs, creating opportunities for rental income, multi-generational living, or increased property value.
Zoning & Property Requirements
Single-Family or Multi-Family Zoning — ADUs are allowed on most residential properties in California.
Lot Size — No minimum lot size is required under state law, though local rules may apply.
Setback Requirements — Generally 4 feet from side and rear property lines for detached ADUs.
Height Limits — Typically 16 feet for detached ADUs, higher if within 1/2 mile of transit.
ADU Size Options
Studio/1 Bedroom — Maximum 850 sq ft.
2+ Bedrooms — Maximum 1,000 sq ft.
Some Jurisdictions — Check local rules for higher limits up to 1,200 sq ft.
Infrastructure Checklist
Water Connection — City water or adequate well capacity. May need to verify GPM for fire requirements.
Sewer/Septic — City sewer or septic system sized for additional dwelling. May need perc test.
Electrical Panel — 200-amp service recommended. May need panel upgrade for separate meter.
Parking — No additional parking required for ADUs within 1/2 mile of public transit.
Siskiyou County Considerations
Building in rural Siskiyou County has unique considerations:
Fire Hazard Zones — Many areas require fire-resistant materials, defensible space, and fire sprinklers.
Well & Septic Limitations — Rural properties may need system upgrades or replacements before ADU approval.
Snow Load Requirements — Higher elevation properties require structural design for significant snow loads.
Permit Timeline — State law requires 60-day approval, but plan for longer with revisions.
Estimated Costs
Permits & Fees: $5,000 - $15,000
Design & Engineering: $5,000 - $15,000
Site Prep & Utilities: $10,000 - $30,000
Construction (per sq ft): $250 - $400
Total (850 sq ft ADU): $230,000 - $380,000
Estimates vary based on site conditions, finishes, and market conditions. Get multiple contractor quotes.
Ready to discuss your options?
I can evaluate your property's ADU potential and connect you with local contractors and designers.
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