Cost to install LA french drain?

$4K–$12K typical perimeter drain.

Basement waterproofing in LA?

$15K–$35K for a full interior-exterior system.

Can my Irvine HOA block an ADU?

No. State law preempts HOA prohibition of ADUs. The HOA can review materials and elevations, but cannot deny the permit outright.

Do I need a CDP for a Newport Beach ADU?

Most of Newport's Balboa Peninsula and oceanfront sit in the Coastal Zone, requiring a CDP. Inland Newport parcels typically do not.

Orange County Drainage & Waterproofing.

LA drainage — french drains, area drains, downspout extensions, sump pumps. Hillside homes get engineered solutions.

Orange County permits are quick when the parcel is in a streamlined city (Irvine, Anaheim, Santa Ana) and slower when the city is small and beachfront (Laguna, Newport's Balboa Peninsula). The most common schedule risk is the master-planned-community HOA — the building permit is fast, but the architectural review committee runs on its own monthly schedule.

Orange County cost band — 2026

$4K – $35K

Surface french drain bottom; full basement system top.

Orange County permit clock

6–10 weeks ministerial

3–7 days for typical drainage system.

Scope — start to keys.

Site assessment
Engineering if needed
Permit
Excavation + install
Backfill + test

What changes about the permit here.

Irvine, Anaheim, Santa Ana: online ADU portals, typically 6–8 weeks ministerial.
Coastal Zone in Laguna, Newport, parts of Huntington — CDP may be required.
Master-planned-community HOAs review independently of city building & safety.
Newport-Inglewood Fault Zone parcels need an Alquist-Priolo geotech investigation.

What moves the Orange County number.

Master-planned HOA design review pushes architectural / cladding budgets 15–25% higher.
Coastal Zone CDP in Laguna / Newport adds $20–60k in soft costs and timeline.
Alquist-Priolo geotech (Newport-Inglewood) commonly $12–30k.
Irvine / Anaheim labor cost runs at LA County median.

In short.

Cost to install LA french drain?: $4K–$12K typical perimeter drain.
Basement waterproofing in LA?: $15K–$35K for a full interior-exterior system.
Can my Irvine HOA block an ADU?: No. State law preempts HOA prohibition of ADUs. The HOA can review materials and elevations, but cannot deny the permit outright.
Do I need a CDP for a Newport Beach ADU?: Most of Newport's Balboa Peninsula and oceanfront sit in the Coastal Zone, requiring a CDP. Inland Newport parcels typically do not.

More we build in Orange County.

Drainage & Waterproofing in nearby LA areas.

Got a Orange County project in mind?

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