Fast, Reliable Garage Conversion ADU Across Moreno Valley
A garage conversion ADU in Moreno Valley typically runs $85,000-$165,000 all-in, from permit drawings through final inspection, with most attached two-car garage conversions landing in the $110,000-$140,000 range. Nearly every project here requires a 200-amp electrical panel upgrade, since the city’s dominant 1980s-90s tract homes were built with 100-amp service that cannot support a separate ADU subpanel and dedicated HVAC load. We’re Ellery ADU Studio, a design-build practice with crews serving Moreno Valley from our Inland Empire office, and we’ve permitted and built garage conversion ADUs across Sunnymead Ranch, Towngate, and the neighborhoods threading off Pigeon Pass Road since 2015. Call (909) 359-6463 to schedule your free estimate. Every quote is written and fixed before any work starts, per Haven Standard, Clause 1.
Why Ellery ADU Studio San Bernardino Is Moreno Valley’s Preferred Garage Conversion ADU Company
We don’t guess at what’s behind your garage walls. Our Garage Conversion ADU team inspects every Moreno Valley project in person before quoting, because the 1980s tract homes that dominate this city hide predictable problems that blow up budgets when they’re discovered mid-project. We’ve designed, permitted, and built over 900 ADUs since 2015, and a significant share of those have been garage conversions in Moreno Valley’s large-lot tracts - the 7,000-10,000+ sq ft parcels that make this city unusually ADU-friendly by Southern California standards.
Our crews are background-checked, uniformed, and licensed, with the license number on every page. Clients receive a documented photo record on every visit - not a summary of how the work felt, but evidence of what was found and what was done. Under the 365-Day Done Right Promise, if the finished ADU is not built to the permitted drawings, we make it right in writing. A live person answers our phones 24/7, and we offer a Free Second Opinion on any written estimate you already have in hand.
Our Garage Conversion ADU Services in Moreno Valley
Attached Garage Conversion
Attached garage conversions are the most common ADU we build in Moreno Valley, and for good reason. The typical two-car garage off a Sunnymead Ranch or Towngate tract house yields 400-480 square feet of conditioned living space, with existing roof structure and at least one shared wall already in place. The catch - and it’s nearly universal here - is that 100-amp electrical service. We price the 200-amp panel upgrade and dedicated ADU subpanel into every attached garage conversion quote from the start, not as a surprise line item after walls are open. The Haven Standard, Clause 1, locks that price at signing.
Detached Garage Conversion
Detached garage conversions in Moreno Valley benefit from the city’s unusually spacious lots, but they carry their own electrical and HVAC complexity. A detached structure needs its own subpanel feed from the upgraded main service, plus a mini-split system sized for Moreno Valley’s enclosed inland valley climate - not the coastal sizing that shorts out under sustained 105-110°F summer highs. We’ve specified and coordinated prefab systems from Cover and Dvele for detached garage conversions where the existing structure’s framing or foundation makes a full rebuild more practical than a retrofit.
Carport Conversion
Carport conversions are less common in Moreno Valley’s garage-heavy housing stock, but they do appear in some 1980s tracts and in homes where a previous owner removed the garage door. A carport conversion requires full enclosure, slab extension or reinforcement, and new electrical and plumbing rough-ins from scratch - typically 15-25% more than an attached garage conversion because there’s no existing wall or roof structure to work with. We inspect the existing post footings and slab thickness before quoting; many carport slabs in this era were poured at 3.5 inches, below the 4-inch minimum for habitable space under current code.
Garage Partition & Bathroom Add
Not every homeowner wants to surrender the entire garage. A garage partition creates a self-contained studio or one-bedroom ADU within a portion of the existing footprint, preserving storage or workshop space on the other side. Adding a bathroom to this layout triggers the drainage issue we see constantly in Moreno Valley: original 1980s slabs sloped for garage drainage, not plumbing fixtures. In a recent Sunnymead Ranch project, the inspector flagged the slab slope on rough inspection. We cut and regraded, set an ejector pump, and pulled the 200-amp upgrade with a dedicated subpanel for the mini-split. The homeowner approved the regrade and pump as a written change order before we poured anything back. No surprise, no scope creep - Haven Standard, Clause 5.
Garage JADU
A Junior ADU, or JADU, is carved from existing living space - in this case, a garage - and must share bathroom facilities with the main house or include its own efficiency kitchen. JADUs cap at 500 square feet and avoid some of the parking replacement requirements that standard ADUs trigger. In Moreno Valley’s multigenerational households, particularly in the neighborhoods near the I-215/SR-60 logistics corridor, garage JADUs offer a lower-cost path to independent living space for extended family. The electrical load is lighter than a full ADU, but we still assess whether the existing 100-amp service can handle the additional circuits without an upgrade.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Moreno Valley
Ellery ADU Studio specifies and coordinates prefab and modular systems from Cover, Dvele, Mighty Buildings, and Boxabl within our single-contract design-build model. For Moreno Valley homeowners considering a detached garage replacement rather than a retrofit, these systems offer factory-precision envelopes with integrated MEP rough-ins, delivered to the Inland Empire and craned onto a foundation we prep and permit. We don’t subcontract the design to a prefab dealer and the build to a separate contractor - the drawings, the permit set, and the construction coordination sit under one written price, one point of accountability. That’s the designer-versus-builder blame gap eliminated before it opens.
Common Garage Conversion ADU Problems We See in Moreno Valley Homes
- 100-amp electrical service that cannot support an ADU subpanel. Every garage conversion needs dedicated circuits for kitchen appliances, bathroom GFCI outlets, lighting, and HVAC. The 100-amp panels original to Moreno Valley’s 1980s-90s tracts simply don’t have the breaker space or service capacity. We identify this on inspection and price the 200-amp upgrade into the initial quote.
- Original slab drainage slope that fails inspection for new plumbing fixtures. Garage slabs were sloped to shed water, not to carry waste. When we add a bathroom or kitchen, the inspector tests that slope. If it fails, we regrade or install an ejector pump - priced and approved in writing before work proceeds, per Haven Standard, Clause 5.
- Mini-split systems undersized for Moreno Valley’s extreme heat. A unit rated for coastal Orange County will short-cycle and fail under sustained 110°F days in this enclosed valley. We size for the actual cooling load, not the catalog default, and we document that sizing in the permit set.
- Aluminum branch wiring in walls opened during conversion. Some 1980s Moreno Valley tracts used aluminum wiring, which is not grandfathered for new circuits and requires pigtailing or full replacement to current copper standards. We photograph what we find and price the remediation before proceeding.
Pricing for Garage Conversion ADU in Moreno Valley, CA
| Service | Typical Range in Moreno Valley |
|---|---|
| Attached garage conversion (400-480 sq ft), all-in | $110,000-$140,000 |
| Detached garage conversion, all-in | $125,000-$165,000 |
| Carport conversion, all-in | $130,000-$170,000 |
| Garage partition & bathroom add | $85,000-$115,000 |
| Garage JADU (500 sq ft max) | $75,000-$105,000 |
| 200-amp panel upgrade + ADU subpanel | $8,500-$14,000 |
| Slab regrade or ejector pump (if needed) | $4,500-$9,500 |
These ranges reflect what we’ve actually quoted and built in Moreno Valley, not national averages. The electrical upgrade and any slab drainage correction are the two variables that move a quote here - not the garage footprint, which is usually straightforward. Every project receives a written, line-item price before any work begins, per Haven Standard, Clause 1. No “call for a quote.” The price is on the page, then confirmed in writing after inspection. Call (909) 359-6463 to schedule your free estimate.
We Also Serve Cities Near Moreno Valley
Our crews work throughout the Inland Empire. If you’re in Moreno Valley or nearby - Colton, Riverside, Redlands, or Grand Terrace - we travel to inspect, quote, and build. Dispatch and scheduling are coordinated from our Riverside-San Bernardino metro office.
Serving Moreno Valley, CA - Our Local Coverage Area
We’re based in the Moreno Valley 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 - Garage Conversion ADU in Moreno Valley
Because the city’s dominant 1980s-90s tract homes were built with 100-amp service that has neither the breaker space nor the capacity for an ADU’s additional circuits - kitchen appliances, bathroom GFCI, lighting, and a dedicated HVAC load. We inspect the panel on every Moreno Valley project and price the upgrade into the initial quote when needed. Call (909) 359-6463 for an exact quote - estimates are free.
It might. Garage slabs were sloped for water drainage, not plumbing waste lines. We test the slope during inspection; if it fails the inspector’s standard for a new bathroom or kitchen, we regrade or install an ejector pump, priced and approved in writing before any concrete is cut. Call (909) 359-6463 for an exact quote - estimates are free.
One sized for sustained 105-110°F summer highs in an enclosed inland valley, not the coastal ratings that dominate contractor catalogs. We calculate the actual cooling load for your garage’s square footage, insulation, and solar exposure, then specify equipment that won’t short-cycle under extreme heat. The sizing documentation is included in your permit set. Call (909) 359-6463 for an exact quote - estimates are free.
Yes. A garage partition with bathroom add preserves storage or workshop space while creating a self-contained studio or one-bedroom unit. This is a popular option in Moreno Valley’s larger garages, particularly in the Sunnymead Ranch and Towngate areas where two-car-plus layouts are common. The scope is smaller, but the electrical and drainage assessments remain the same. Call (909) 359-6463 for an exact quote - estimates are free.
We inspect in person before quoting on every garage conversion ADU in Moreno Valley. Photos can’t reveal aluminum wiring, panel capacity, slab slope, or framing condition - the four factors that determine whether your quote moves. The inspection is free, and you receive a written, line-item price before any work begins, per Haven Standard, Clause 1. Call (909) 359-6463 to schedule.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Moreno Valley since 2015.