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Detached ADU
A stand-alone unit built new on your lot, the format state law protects to at least 800 square feet.
Custom homes, additions & ADUs · El Dorado County
Custom Homes, Additions & ADUs
Ground-up custom homes, room additions, detached ADUs, and garage conversions across El Dorado County and the Highway 50 corridor, built by a Placerville-based general contractor licensed since 2004.
- CA License #835432
- Bonded & Fully Insured
- EPA Lead-Safe Certified
- Since 2004
ADU types
ADU types we build
Detached, garage conversion, or attached. Each format in one line.
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Garage conversion
An existing garage becomes a legal dwelling inside its own footprint.
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Attached ADU & JADU
An addition tied to the main house, or a junior ADU carved from space within it.
The permit path
The El Dorado County permit path
The desks an El Dorado County ADU application crosses. CCI manages permitting and inspections end to end.
- 01
Design & engineering
Site plan, floor plan, structural calcs.
- 02
Building Services plan check
County review of the full permit set.
- 03
Environmental Management
Septic/OWTS capacity review where applicable.
- 04
Fire district / WUI review
Fire-severity and access review where applicable.
- 05
Permit issuance
Fees paid, permit in hand, work begins.
- 06
Inspections to final
County inspections through final sign-off.
Straight answer on cost
What an ADU costs to build in El Dorado County
The honest answer is a range set by your site, not the floor plan. Slope, septic, and utility runs price a foothill lot differently than Sacramento flatland.
CSLB #835432 Since 2004 Fully insured
Detached ADU, all-in
By estimate
Range from real El Dorado County estimates
- Site work on slope
- Engineered foundations, grading, retaining. The hillside line item.
- Utilities & septic
- Service runs, panel capacity, and county septic scope.
- Finish level
- Interior selections move the top of the range, not the bottom.
Ready to price your ADU?
An estimate on your actual lot, with your slope, your septic, and your utility run, from a Placerville-based GC licensed since 2004.
CSLB #835432 · Bonded · Fully insured · Quick response during business hours
El Dorado County ADU questions, answered first
Every answer leads with the answer, then the code cites that back it up.
How much does it cost to build an ADU in El Dorado County?
The honest answer is a range, and your site sets it more than your floor plan. CCI quotes from real El Dorado County estimates, and three drivers move the number most: site work on slope, utility and septic scope, and finish level. Foothill lots price differently than Sacramento flatland.
How long does an ADU take from design to move-in?
Plan in three phases: design and engineering, permitting, and construction. State law puts El Dorado County on a fixed review clock: Gov. Code §66317 requires the county to approve or deny a complete ADU application within 60 days, or it’s deemed approved. That clock sets the floor for the permit phase.
Can El Dorado County deny my ADU?
No, not a code-compliant application. California law makes ADU approval ministerial, with no public hearing and no neighbor veto (Gov. Code §66317; state HCD ADU Handbook, March 2026 edition). What the county can require is compliance on setbacks, septic capacity, and fire standards. That is exactly the feasibility work CCI does up front.
How big can my ADU be?
State law protects an ADU of at least 800 square feet with 4-foot side and rear setbacks (Gov. Code §§66321, 66314). ADUs of 750 square feet or less are also exempt from local impact fees (Gov. Code §66311.5); larger units pay proportionately.
Can I build an ADU on a septic system?
Yes, with a county septic capacity evaluation through Environmental Management. El Dorado County runs its own state-approved Local Agency Management Program (LAMP) for onsite wastewater, and reviews whether your existing system can carry the added bedrooms; if it can’t, the fix gets scoped and priced before construction, not discovered during it.
Can I build an ADU on a sloped lot?
Yes. Slope changes cost, not feasibility. It takes engineered foundations and sometimes grading or retaining walls, and structural work like beams, foundations, and load paths is CCI’s in-house core. See our structural beam replacement work.
Do ADUs in fire zones need special construction?
Yes. In WUI and fire-severity zones, ignition-resistant construction standards apply under the California Wildland-Urban Interface Code (Title 24, Part 7). Sprinklers follow the state ADU rule (Gov. Code §66314): not required in the ADU unless they’re required for the main house, and fire-district coordination is part of the permit path here.
Do I have to live on the property to rent out my ADU?
State law bars owner-occupancy requirements on standard ADUs (Gov. Code §66315), so you can rent it long-term without living on site, or house family with a separate front door on the same land. Junior ADUs are the exception (Gov. Code §66333). Vacation rental is off the table, though: El Dorado County’s ordinance (County Code ch. 5.56) does not permit short-term rentals in ADUs.
Will an ADU raise my property taxes on my whole house?
No. Only the ADU’s added value is assessed. Per the State Board of Equalization, your existing home and land are not reassessed when an ADU is completed; the new construction is assessed at market value and added on top of your current bill.
Why choose CCI to build your ADU?
Because foothill ADUs are structural jobs, and structural work like beams, foundations, and load paths is CCI’s in-house core, not a subbed-out mystery. Licensed since 2004 (CSLB #835432), bonded, fully insured, EPA Lead-Safe, and OSHA compliant, with owner Jon Saunders or a highly qualified member of his team as your one point of contact, and the same crew behind our structural beam replacement work.