Are ADUs worth the investment?

ADUs (Accessory Dwelling Units) have become one of the strongest value-add plays in California real estate over the last 5 years. California legislation has dramatically streamlined permitting.

Build cost ranges: - Garage conversion ADU: $100K-$200K depending on size and condition. - Detached new-build ADU (400-800 sqft): $200K-$400K. - Junior ADU (within existing house): $80K-$150K.

Value-add typically: - Rental income: $1,500-$3,500/month depending on size and pocket. - Resale value increase: $200K-$500K on the home's value for a permitted, well-built ADU.

ROI math (East Bay duplex equivalent strategy): - Build a 600 sqft ADU for $300K. - Rent it for $2,500/month = $30K annual income. - Property value increases by $350K at next sale. - After 5 years: $150K rent + $350K equity = $500K return on $300K invested.

Permitting realities (California, 2026): - State law preempts most local restrictions on ADU permitting. - Cities cannot require parking for ADUs near transit. - Cities cannot require owner occupancy for ADUs as a condition of permitting. - HOA restrictions on ADUs have been limited (with some exceptions).

Where to be careful: - Coastal Commission jurisdictions have additional rules. - Hillside lots and creek-adjacent lots add costs. - Specific city requirements still vary on setbacks, height, design review.

Roger has worked with several ADU projects in the East Bay and can refer you to architects and contractors with East Bay-specific experience.

This is a starting point, not the complete answer. Real estate decisions depend on details that don't fit in an FAQ — your numbers, your timeline, your family situation. Call (510) 504-0402 during the day, text or call (406) 205-9003 anytime, or email roger@grubb.net. I'll walk you through it personally.