ADU in Wrightwood, CA
Junior ADU & Interior Conversion in Wrightwood typically runs $85,000-$165,000 all-in, drawings through final inspection, because most projects start with a 1940s-1970s cabin never designed for full-time occupancy plus a second unit. ADU Site Prep & Utilities adds $25,000-$75,000 before construction starts, driven by septic capacity evaluations and snow-load engineering that flatland projects skip entirely. Call (760) 493-7752 and we’ll schedule your free estimate with a written price before any work begins.
We’re Ellery ADU Studio, a design-build practice that handles drawings, permits, and construction under one contract at one written price. Our Los Angeles office coordinates dispatch and scheduling for Wrightwood crews. We’ve specified and coordinated prefab systems from home brands including Plant Prefab and Tuff Shed, but most Wrightwood jobs require custom engineering that catalog plans can’t satisfy.
Why Wrightwood Homes Are Different
Wrightwood sits at roughly 6,000 feet in the Swarthout Valley, and that elevation changes everything about ADU construction. San Bernardino County requires snow load calculations specific to this zone, and most pre-approved ADU plans marketed across Southern California fail the required roof live load threshold. Heavy snow loads can exceed 60 psf, making off-the-shelf plans functionally dead on arrival without costly re-engineering.
The housing stock compounds the challenge. Most Wrightwood homes are mid-century vacation cabins and A-frames built as seasonal weekend retreats, with undersized electrical panels, aging plumbing, and private septic systems sized for intermittent use. Nearly every ADU permit triggers a mandatory septic capacity evaluation, and upgrades are common. The High Fire Hazard Severity Zone adds WUI requirements: Class A roofing, ember-resistant vents, and ignition-resistant siding on new builds. Proximity to Mountain High ski resort also drives strong demand for short-term rental ADUs, giving homeowners a clearer ROI case than most mountain towns.
Our Main Wrightwood Services
Most Wrightwood homeowners start with one of these three services, then add site prep and utilities as the permit set reveals what’s required.
ADU Design & Permitting in Wrightwood
We produce permit-ready drawings that account for Wrightwood’s snow loads, WUI requirements, and septic constraints from the first sheet. San Bernardino County Building and Safety rejects flatland plans here regularly; our permit sets include elevation-specific structural calculations and septic pre-assessment documentation. ADU Design & Permitting in Wrightwood covers the full package: site plan, floor plans, elevations, structural details, and energy calculations.
Garage Conversion ADU in Wrightwood
Detached garages and storage outbuildings are common conversion targets in Wrightwood, but nearly all require electrical panel upgrades and septic reassessment before permits issue. We evaluate the existing slab, roof structure, and utility capacity during our first site visit, then quote a single written price for drawings, permits, and construction. Garage Conversion ADU in Wrightwood includes snow-load roof verification and WUI-compliant exterior finishes.
New Detached ADU in Wrightwood
New detached units in Wrightwood face the full mountain build requirements: snow-load engineering, WUI-compliant materials, and septic capacity proof. We coordinate structural engineering, soil reports, and utility routing through a single contract. New Detached ADU in Wrightwood typically involves more site prep than conversion projects, but offers maximum rental income potential in a market where short-term demand stays strong year-round.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Junior ADU & Interior Conversion in Wrightwood
Junior ADU & Interior Conversion in Wrightwood solves a specific problem: converting existing interior space into a permitted second unit without expanding the building footprint. Most Wrightwood cabins have underutilized basements, storage rooms, or attached additions that predate modern codes, and Junior ADU & Interior Conversion unlocks this square footage under JADU rules that allow shared utility connections and reduced parking requirements. The catch is that 1940s-1970s construction often lacks the headroom, egress windows, and fire separation that San Bernardino County now requires, so our permit sets address these gaps explicitly.
Basement ADU
Signs you need it
Your cabin has a partial or full basement used for storage, with ceiling height at or near 7 feet 6 inches and no legal egress window.
What it costs in Wrightwood
Basement ADU conversions in Wrightwood typically run $95,000-$175,000, including excavation for egress windows, moisture barrier installation, and headroom compliance work.
How we do it
We measure existing headroom, design the egress window cut and retaining wall, produce the permit set with structural verification, then build to the drawings with a documented photo record on every visit.
Room-to-ADU Conversion
Signs you need it
You have an attached bedroom, den, or enclosed porch with separate exterior access potential and a floor area between 150 and 500 square feet.
What it costs in Wrightwood
Room-to-ADU conversions in Wrightwood typically run $75,000-$140,000, including fire-rated separation from the main unit, kitchenette rough-in, and separate meter or sub-meter installation.
How we do it
We verify the existing foundation and framing can support the new use, design the fire separation and utility branch lines, permit through San Bernardino County, then construct with the Haven Standard photo record at each phase.
What Junior ADU & Interior Conversion Costs in Wrightwood
| Item | Typical range in Wrightwood |
|---|---|
| Basement ADU conversion | $95,000 - $175,000 |
| Room-to-ADU conversion | $75,000 - $140,000 |
| Above-garage ADU (interior only) | $85,000 - $155,000 |
Can a JADU share utilities with the main house?
Yes, California JADU law allows shared water, gas, and electric service with the main residence, though San Bernardino County requires a sub-meter or clear utility allocation in the lease. Call (760) 493-7752 and we’ll review your specific setup during the free estimate.
Do Wrightwood JADUs need separate parking?
No, JADUs are exempt from separate parking requirements under state law, which matters on Wrightwood’s steep, narrow lots where adding a parking space often costs more than the ADU itself. Call (760) 493-7752 for a written quote on your conversion.
ADU Site Prep & Utilities in Wrightwood
ADU Site Prep & Utilities in Wrightwood is where most projects stall without professional coordination, because private septic systems, undersized electrical panels, and snow-load foundations aren’t visible in online ADU cost calculators. ADU Site Prep & Utilities handles the infrastructure that must be proven before San Bernardino County issues a building permit, and we quote this work with the same written upfront price as our design-build packages.
Electrical Panel Upgrade
Signs you need it
Your existing panel is rated below 200 amps, has no open breaker spaces, or shows corrosion from mountain humidity cycles.
What it costs in Wrightwood
Electrical panel upgrades in Wrightwood typically run $4,500-$12,000, including trenching for underground service, new meter base, and SCE coordination.
How we do it
We verify load calculations for the ADU plus existing demand, pull the permit through San Bernardino County, coordinate Southern California Edison for service disconnect, then install with inspection scheduling.
Plumbing Lateral & Septic
Signs you need it
Your property has a private septic system installed before 1990, or San Bernardino County Environmental Health requires a capacity evaluation for added occupancy.
What it costs in Wrightwood
Septic evaluation, design, and replacement in Wrightwood typically run $15,000-$45,000, including perc testing, engineered leach field, and county approval.
How we do it
We coordinate the septic evaluation, produce the engineered design if replacement is required, permit through Environmental Health, then install with documented photo record at each excavation phase.
What ADU Site Prep & Utilities Costs in Wrightwood
| Item | Typical range in Wrightwood |
|---|---|
| Electrical panel upgrade | $4,500 - $12,000 |
| Septic evaluation and replacement | $15,000 - $45,000 |
| Foundation and grading (new detached) | $18,000 - $55,000 |
Does site prep happen before or after design?
We evaluate site conditions during our initial site visit and include prep scope in the written quote, but physical work starts only after permits are approved to avoid double excavation. Call (760) 493-7752 to schedule your evaluation.
Will SCE and the county coordinate with Ellery directly?
Yes, we handle all utility and agency coordination as part of our single-contract model; you receive one point of contact and one written price covering every interaction. Call (760) 493-7752 for specifics on your property.
Brands We Service in Wrightwood
We specify and coordinate prefab and modular systems from Plant Prefab, Tuff Shed, and James Hardie, though most Wrightwood jobs require custom engineering beyond catalog offerings. When a prefab solution fits after snow-load and WUI review, we source through our brands with the same single-contract warranty. Local parts and materials are stocked within 48 hours for standard repairs.
Pricing for ADU in Wrightwood, CA
| Service | Typical range in Wrightwood |
|---|---|
| Junior ADU & Interior Conversion (basement) | $95,000 - $175,000 |
| Junior ADU & Interior Conversion (room conversion) | $75,000 - $140,000 |
| Junior ADU & Interior Conversion (above-garage) | $85,000 - $155,000 |
| ADU Site Prep: Electrical panel upgrade | $4,500 - $12,000 |
| ADU Site Prep: Septic evaluation and replacement | $15,000 - $45,000 |
| ADU Site Prep: Foundation and grading | $18,000 - $55,000 |
Prices in Wrightwood run higher than flatland projects for three reasons: snow-load structural engineering adds design hours, WUI-compliant materials cost more than standard finishes, and septic work is nearly universal on older parcels. Under Haven Standard Clause 1, your written price is locked before any work starts; no change orders for conditions we should have found during site evaluation.
Neighborhoods We Serve in Wrightwood
We work across Wrightwood’s unincorporated mountain community, from the original village core to newer development on the valley’s edges. Most properties share the same core challenges: private septic, snow-load requirements, and WUI construction rules. Our crews are dispatched from the Los Angeles office with same-week scheduling availability for site evaluations.
- Swarthout Valley core
- Mountain High vicinity
- Blue Ridge area
- Oakwood homesites
- Upper Wrightwood slopes
Service Area - Cities Near Wrightwood
Ellery ADU Studio serves mountain and high-desert communities throughout San Bernardino County. We regularly coordinate projects in Phelan, CA, Hesperia, CA, Fontana, CA, and Crestline, CA, where many of the same county permit processes and fire-zone requirements apply. Scheduling and dispatch are coordinated from our Los Angeles office with local crews assigned by region.
Serving Wrightwood, CA - Our Local Coverage Area
We’re based in the Wrightwood area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU in Wrightwood
County review typically runs 8-14 weeks for a complete submittal, but Wrightwood projects often face one additional cycle for snow-load engineering verification and septic capacity approval. We front-load these requirements in our permit set to minimize delays.
New detached ADUs in Wrightwood’s High Fire Hazard Severity Zone require fire sprinklers if the main house has them; JADUs and conversions follow the existing residence standard. We verify this during our first site visit and include it in the written scope.
No, San Bernardino County Building and Safety requires snow load calculations specific to Wrightwood’s 6,000-foot elevation zone, and most catalog plans fail the roof live load threshold. Our permit sets are engineered for your specific parcel from the first sheet.
Call (760) 493-7752 to schedule your free estimate. You’ll receive a written price before any work starts, a documented photo record on every visit, and the 365-Day Done Right Promise in writing. Nadia Ellery and the team at Ellery ADU Studio handle every project under one contract at one price.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Wrightwood Customers Say
"They walked us through setbacks and utility capacity before we paid anything, and told us one of our two options was not going to get approved."
- Mireille T."The rental income has covered the payment since the second month. They were realistic about the numbers rather than optimistic."
- Odette N."The permit set and the build were one contract with one number. Our neighbours used two firms and spent a year watching them blame each other."
- Helena V.