Hills & Canyons · FAQ

Hills & Canyons ADU questions, answered

Questions we get on almost every Hills & Canyons site walk. If yours isn't here, ask us — we answer everything before you commit.

Does the Baseline Hillside Ordinance kill my ADU?

Almost never. State ADU law overrides local FAR limits up to 800 sqft, and many hillside lots can fit a full 1,200 sqft attached ADU even under BHO.

How much does hillside geotech add?

Plan on $8–25k for the report itself. The downstream cost — caissons, retaining walls, deeper foundations — is where the real budget impact lives.

What's the haul-route permit?

HCR (Hillside Construction Regulation) limits truck size and operating hours on hillside streets. We file the haul-route permit alongside the building permit, not after.

Do I need Director's review on Mulholland?

Only if your parcel is inside the Mulholland Specific Plan corridor. If it is, expect 6–12 weeks of additional review before LADBS will accept the package.

Can I do a basement ADU on a downslope lot?

Often the cleanest option — lower retaining cost, hidden from street, and counts as a conversion under state law if the existing structure already has the basement.

Reference

Terms and guides for this page

Glossary terms

BHO (Baseline Hillside Ordinance)
City of LA rules governing residential construction on hillside lots — height, grading, haul routes.
Soils Report
Engineering study of subsurface soil conditions, required for hillside and certain ADU lots.
LADBS (LA Department of Building and Safety)
The City of Los Angeles agency that issues building permits and conducts inspections.
LADWP (LA Department of Water and Power)
City of LA's water and electrical utility — handles ADU service connections and meter sets.
HPOZ (Historic Preservation Overlay Zone)
City of LA designation that imposes design review on alterations within a historic neighborhood.
ADU (Accessory Dwelling Unit)
A self-contained second home on a residential lot, with its own kitchen, bath, and entrance.

Field guides

The Los Angeles ADU permit process, step by step
Permitting an ADU inside the City of Los Angeles takes about 8–11 weeks of plan check (LADBS) plus 2–4 weeks of pre-submittal prep. State law caps ministerial review at 60 days from a complete submittal. Total city + utility fees for a 700 sqft detached ADU typically run $13,000–$26,000.