How United Build Partners helps Whittier homeowners
We're an ADU advisory and contractor-matching service, not the construction company. We start with a free review of your Whittier property and goals, help you understand whether one of the city's pre-approved plans fits your lot, and — when it's a good fit — connect you with up to three contractors in our network.
ADU rules and permitting in Whittier
Whittier's ADU standards build on the same statewide floor every California city follows — ministerial review and a 60-day clock on complete applications (see our California ADU laws guide). Whittier's Community Development Department offers Preapproved ADU Plans, currently limited to 1-story, detached structures, intended to speed up the permitting process for homeowners who use one of the pre-vetted designs.
What's specific to Whittier
- Pre-approved plans: currently available only for single-story, detached ADU designs — an attached ADU or a two-story design would need to go through standard custom review instead.
- Unit allowance: Whittier's local code generally allows one ADU per existing single-family parcel, on R-E and R-1 zoned properties (including certain multi-family zoned properties with an existing single owner-occupied dwelling as the primary use).
- Size: an attached ADU is capped at 50% of the main structure's living area or 1,200 square feet, whichever is less; a detached ADU may reach up to 1,200 square feet. A Junior ADU is capped at 500 square feet.
- Minimum size: at least 150 square feet, to accommodate an efficiency unit.
Property and lot considerations
Because Whittier's pre-approved plans are limited to single-story detached designs, homeowners hoping to build up rather than out, or to build attached to their existing home, will need a custom-designed project instead. A property review can help you figure out which path — pre-approved or custom — best fits your specific lot and goals.
Common ADU types for Whittier homeowners
Homeowners drawn to speed and lower design cost often choose a detached ADU using one of Whittier's pre-approved plans. Homeowners with an existing garage often consider a garage conversion instead, which follows the standard custom-review process. A Junior ADU remains the lowest-cost path for converting existing interior space.
Cost factors in Whittier
Construction costs in Whittier generally track the same range as the rest of our Los Angeles County service area — see our full ADU cost guide. Using a pre-approved plan can meaningfully reduce design costs and permitting time compared with a fully custom design.
Financing your Whittier ADU
Most homeowners fund construction through a HELOC, cash-out refinance, or dedicated construction loan — see our ADU financing overview for how each works.
Rental income and property value in Whittier
Whittier's established single-family neighborhoods support real rental demand for many homeowners, though actual achievable rent depends heavily on your specific neighborhood and unit — we don't have a verified, current rent figure to quote. See our ADU rental income guide and ROI calculator to work through your own numbers.
How our process works
Frequently asked questions
Yes — the city's Community Development Department offers Preapproved ADU Plans, currently limited to 1-story, detached structures, designed to speed up permitting compared to a fully custom design.
Not currently — Whittier's pre-approved plans are limited to single-story, detached designs. An attached ADU would go through the standard custom review process instead.
Whittier's local code generally allows one ADU per existing single-family parcel. See our guide to how many ADUs you can build for the broader statewide framework, including Junior ADU eligibility.