ADU in San Bernardino, CA
Junior ADU & Interior Conversion in San Bernardino typically runs $85,000-$165,000 all-in, drawings through final inspection, while ADU Site Prep & Utilities adds $15,000-$55,000 depending on whether your 1940s-1970s home needs a panel upgrade or sewer lateral replacement. We’re Ellery ADU Studio, and our Inland Empire office coordinates crews across San Bernardino’s postwar neighborhoods daily. Call (840) 212-3065 to schedule your free estimate.
Why San Bernardino Homes Are Different
San Bernardino’s northern foothill neighborhoods sit within or directly adjacent to Alquist-Priolo Earthquake Fault Zones tied to the San Andreas Fault, which traces along the city’s northern edge. ADU projects in the North End and foothill areas routinely require fault-rupture hazard studies and enhanced seismic design that contractors in neighboring cities almost never encounter.
Layered on top of that, San Bernardino’s Building & Safety department - still lean after the city’s 2012-2017 bankruptcy reorganization - runs slower plan-check cycles than most Inland Empire peers. Local permit-process knowledge is a genuine competitive advantage here. The housing stock is dominated by post-WWII single-family homes on large 6,000-9,000+ sq ft lots with detached two-car garages, and these homes frequently carry original 100-amp panels, galvanized supply lines, and minimal wall insulation. Utility upgrades bundle into nearly every ADU scope before the city signs off.
Summer highs of 105-112°F mean ADU HVAC systems must be significantly oversized compared to coastal climates. Foothill parcels fall under Very High Fire Hazard Severity Zone designation, mandating ember-resistant venting and ignition-resistant exterior materials. North-end parcels near Shandin Hills frequently trigger CGS fault-zone reviews that surprise homeowners with $3,000-$8,000 in geological consulting fees - a cost experienced San Bernardino contractors build into their discovery checklist from the first site visit.
Our Main San Bernardino Services
San Bernardino homeowners most often start with one of these three core services, each with its own dedicated page and local pricing.
ADU Design & Permitting in San Bernardino
Our permit set is the core product, not an afterthought. In San Bernardino, that means navigating slower plan-check cycles and fault-zone requirements that out-of-area designers miss. We produce construction documents, structural calcs, and Title 24 energy compliance as a single package. ADU Design & Permitting in San Bernardino
Garage Conversion ADU in San Bernardino
With detached two-car garages on nearly every postwar lot, garage conversions are San Bernardino’s most common ADU entry point. We assess slab condition, ceiling height, and utility routing before quoting. Garage Conversion ADU in San Bernardino
New Detached ADU in San Bernardino
New detached units in San Bernardino face setback rules, fire-hazard material requirements in foothill zones, and potential fault-rupture studies in the North End. We coordinate geotechnical review, structural design, and prefab specification under one contract. New Detached ADU in San Bernardino
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 San Bernardino
Junior ADU & Interior Conversion in San Bernardino converts existing interior space - basements, attics, attached rooms, or garage upper levels - into permitted dwelling units without expanding the building footprint. This works particularly well in San Bernardino’s older postwar stock, where large lots mean generous existing floor plans but original systems need replacement. Junior ADU & Interior Conversion covers the full scope from code analysis to final inspection.
Room-to-ADU Conversion
Signs you need it
You have 400+ square feet of underused attached space - a former den, bonus room, or enclosed patio - with separate exterior access already or easily added.
What it costs in San Bernardino
Room-to-ADU conversions in San Bernardino typically run $85,000-$140,000 all-in, including the kitchenette, bathroom, permit set, and utility tie-ins.
How we do it
We verify ceiling height for habitability, design the wet-wall layout for drainage fall, produce the full permit set, and manage the trade sequencing so you’re not living around open walls for months.
Interior JADU
Signs you need it
You need a compact rental unit inside your primary residence, under 500 square feet, with efficiency kitchen and separate entrance, without touching the exterior envelope.
What it costs in San Bernardino
Interior JADUs in San Bernardino typically run $75,000-$125,000 all-in, drawings through final inspection, assuming no panel or sewer lateral upgrades.
How we do it
We analyze the existing floor plan for code-compliant egress, design the compact wet core, produce the JADU-specific permit set, and coordinate the inspection sequence with San Bernardino Building & Safety.
What Junior ADU & Interior Conversion Costs in San Bernardino
| Item | Typical range in San Bernardino |
|---|---|
| Room-to-ADU conversion, all-in | $85,000-$140,000 |
| Interior JADU, all-in | $75,000-$125,000 |
| Above-garage ADU (if structurally sound) | $110,000-$165,000 |
Do I need a separate meter for a Junior ADU in San Bernardino?
No - California state law prohibits cities from requiring separate utility meters for JADUs, though you may opt for one. Call (840) 212-3065 and we’ll walk through the trade-offs for your specific San Bernardino property.
Will my 1940s wiring pass inspection for a Junior ADU?
Original cloth-insulated or ungrounded circuits will not pass; we budget panel and circuit upgrades into every pre-1970 San Bernardino conversion scope. Call (840) 212-3065 for a free estimate with the electrical line item spelled out.
ADU Site Prep & Utilities in San Bernardino
ADU Site Prep & Utilities in San Bernardino addresses the conditions that stop most projects before design begins: original 100-amp panels, galvanized supply lines, undersized sewer laterals, and slabs that won’t carry conversion loads. In a city where summer heat hits 112°F and foothill fire zones mandate ignition-resistant materials, getting the site and utilities right is not preliminary work - it’s the foundation of the entire project. ADU Site Prep & Utilities integrates with our design-build contract so nothing gets orphaned between trades.
Electrical Panel Upgrade
Signs you need it
Your main panel is 100 amps, has no open breaker spaces, or still uses fuses - all common in San Bernardino’s postwar housing stock.
What it costs in San Bernardino
Electrical panel upgrades in San Bernardino typically run $4,500-$9,500, including the new 200-amp service, permit, and SCE coordination.
How we do it
We verify SCE’s service lateral capacity, design the new panel location for ADU subpanel routing, pull the permit, and schedule the utility disconnect-reconnect.
Plumbing Lateral
Signs you need it
Your home has galvanized supply lines, a 3-inch sewer main, or documented backups - any of which will fail San Bernardino’s ADU plumbing inspection.
What it costs in San Bernardino
Plumbing lateral replacement in San Bernardino typically runs $8,500-$18,000, including trenching, new ABS sewer line, and water service upgrade to 1-inch.
How we do it
We camera the existing line, locate the city tap, design the routing to avoid mature landscaping where possible, and coordinate the trench inspection with San Bernardino’s combined sewer district.
What ADU Site Prep & Utilities Costs in San Bernardino
| Item | Typical range in San Bernardino |
|---|---|
| Electrical panel upgrade to 200A | $4,500-$9,500 |
| Plumbing lateral replacement | $8,500-$18,000 |
| Foundation repair or reinforcement for conversion | $5,500-$15,000 |
Can I do site prep before hiring an ADU designer?
You can, but we don’t recommend it - the panel location and sewer routing we design for may differ from what a standalone electrician or plumber installs. Call (840) 212-3065 and we’ll sequence it under one contract.
Does San Bernardino require sewer capacity testing before ADU approval?
San Bernardino Building & Safety may require a sewer lateral inspection or capacity letter for detached ADUs; we verify this at permit submittal and build any required testing into our scope. Call (840) 212-3065 for a free estimate.
Brands We Service in San Bernardino
We specify and coordinate prefab and modular systems from Abodu, Cover, and Mighty Buildings within our single-contract design-build model. Our Inland Empire office stocks common connection hardware and flashing kits for these brands, with most San Bernardino prefab coordination questions answered same-day. See our brands for the full list.
Pricing for ADU in San Bernardino, CA
| Service | Typical range in San Bernardino |
|---|---|
| Room-to-ADU conversion | $85,000-$140,000 |
| Interior JADU | $75,000-$125,000 |
| Above-garage ADU | $110,000-$165,000 |
| Electrical panel upgrade | $4,500-$9,500 |
| Plumbing lateral replacement | $8,500-$18,000 |
| Foundation repair/reinforcement | $5,500-$15,000 |
| CGS fault-zone study (North End/foothill) | $3,000-$8,000 |
| HVAC upsizing for 105-112°F climate | $2,500-$6,500 premium over baseline |
What pushes price up in San Bernardino: Alquist-Priolo fault-zone studies in northern neighborhoods, fire-hazard material upgrades in foothill zones, and the utility upgrades bundled into nearly every pre-1970 home. Under Haven Standard Clause 1, every project is quoted with a written price before any work begins - no call-for-pricing, no door-side upsells.
Neighborhoods We Serve in San Bernardino
Our crews work across San Bernardino’s full range of housing eras and terrain conditions, from the flat central valley to the fault-adjacent foothills. Dispatch and scheduling are coordinated from our Inland Empire office, with most San Bernardino properties reached within standard response windows.
- North End / Shandin Hills
- Del Rosa
- Arrowhead
- Seccombe Lake
- California State University area
Service Area - Cities Near San Bernardino
Ellery ADU Studio serves the full Inland Empire corridor from our regional office. We regularly coordinate ADU projects in Riverside, CA, Fontana, CA, Rancho Cucamonga, CA, and Ontario, CA - each with its own permit timelines, utility conditions, and local requirements that we track separately from San Bernardino’s.
Serving San Bernardino, CA - Our Local Coverage Area
We’re based in the San Bernardino 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 San Bernardino
San Bernardino’s Building & Safety department typically runs 8-14 weeks for plan check, longer than Riverside or Fontana due to lean staffing post-bankruptcy. We mitigate this by submitting a complete permit set upfront and responding to corrections in 48 hours.
California law limits HOA prohibition of ADUs, but HOAs can impose reasonable design and screening standards. We review your CC&Rs during discovery and flag any enforceable restrictions before design begins.
Parcels in or near Alquist-Priolo zones along the San Andreas Fault trace typically require a CGS fault-rupture hazard study, adding $3,000-$8,000 and 2-4 weeks. We check this on the first site visit and build it into your written quote if required.
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 San Bernardino Customers Say
"Handled the whole planning process. We went to one hearing and that was it."
- Rowena C."The rental income has covered the payment since the second month. They were realistic about the numbers rather than optimistic."
- Odette N."Garage conversion finished on the drawings and close to the schedule. They were honest that the sewer connection was the unknown, and it was."
- Arjun D.