ADU in Covina, CA
Junior ADU & Interior Conversion in Covina typically runs $85,000-$165,000 all-in, drawings through final inspection, while ADU Site Prep & Utilities adds $18,000-$55,000 depending on whether your 1950s ranch needs a full electrical service upgrade. We’re Ellery ADU Studio, and we’ve found Covina’s post-war housing stock - concrete-slab ranches with 100-amp panels and detached garages on 7,500-square-foot lots - creates a predictable but specific set of conditions for interior conversions. Our Los Angeles office coordinates scheduling and dispatch; crews serve Covina directly. Call (657) 286-7915 for a free estimate with a written price before any work starts.
Why Covina Homes Are Different
Covina’s residential grid was carved from citrus groves in the 1950s and 1960s, and the building patterns from that era still dictate what an ADU project looks like today. Most lots fall between 7,000 and 9,500 square feet, with a single-story ranch house set toward the front and a detached two-car garage accessed from a rear alley. The original construction was economical: 4-inch concrete slab, no subpanel in the garage, galvanized or early copper water supply, and a 100-amp electrical service that barely supported the house’s original load.
The climate here is inland San Gabriel Valley, not coastal. Summer highs reach 95-105°F, and the marine layer rarely makes it this far east. A detached garage conversion - Covina’s most common ADU type - starts with zero existing HVAC. A ductless mini-split isn’t an upgrade; it’s a requirement, and it adds to the mechanical budget in ways that attached ADU projects in cooler LA County zones don’t face.
Permitting moves through Covina’s own Community Development Department, which runs faster than LA County’s plan-check queue for unincorporated areas. But the electrical bottleneck is Southern California Edison, not the city. Nearly every ADU triggers a 200-amp service upgrade, and SCE’s scheduling backlog in this SGV zone adds 6-10 weeks if the request isn’t filed concurrently with the permit application.
Our Main Covina Services
Most Covina homeowners start with one of these three project types, depending on whether they’re converting existing space or building new.
ADU Design & Permitting in Covina
We produce the full permit set - structural, Title 24 energy calcs, and fire separation details - as a standalone deliverable or as the first phase of a design-build contract. Covina’s plan-checkers know our drawings; we submit concurrently with SCE upgrade requests to protect the timeline. ADU Design & Permitting in Covina covers everything from feasibility to stamped plans.
Garage Conversion ADU in Covina
The dominant Covina project: detached two-car garages with alley access, no existing subpanel, and a slab that usually needs moisture barrier and insulation before flooring goes in. We handle the structural, mechanical, and utility tie-ins under one contract. Garage Conversion ADU in Covina is our most called-about service here.
New Detached ADU in Covina
For homeowners whose garage is already optimized for parking or whose lot geometry favors a rear-yard placement, we design and build new detached units from foundation to final inspection. Setback rules in Covina - the distance from property line to structure - are specific to each zoning envelope, and we verify them before the first drawing. New Detached ADU in Covina starts with a site feasibility review.
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 Covina
Junior ADU & Interior Conversion in Covina solves a specific problem: homeowners who want rental income or multigenerational housing without giving up their garage or building new in the backyard. Covina’s ranch homes - compact, single-story, often with underutilized basements or attached rooms - are structurally straightforward for this work, but the 100-amp service panels and original plumbing mean every interior conversion needs utility planning from day one. We handle Junior ADU & Interior Conversion as a single contract, so the designer can’t blame the electrician when the panel won’t support the new kitchen.
Room-to-ADU Conversion
Signs you need it
You have a attached bedroom or den with separate exterior access that sits unused, and you want a self-contained rental unit without altering the home’s footprint.
What it costs in Covina
Room-to-ADU conversions in Covina typically run $85,000-$140,000 all-in, including the required kitchenette, bathroom addition, and separate meter or submeter setup.
How we do it
We verify the existing slab and framing can support the new loads, design the kitchenette layout to meet JADU square-footage limits, run plumbing and electrical from the main service, and produce the full permit set for Covina plan check.
Interior JADU
Signs you need it
You’re looking for the smallest permissible ADU type - under 500 square feet, inside your existing home, with owner-occupancy required - to maximize rental income with minimal construction.
What it costs in Covina
Interior JADUs in Covina typically cost $75,000-$125,000, with the lower end applying when plumbing and electrical tie-ins are short runs from existing infrastructure.
How we do it
We identify the optimal interior zone for the kitchenette and bathroom, verify fire separation from the main dwelling, design to JADU efficiency standards, and coordinate the owner-occupancy affidavit with Covina’s Community Development Department.
What Junior ADU & Interior Conversion Costs in Covina
| Item | Typical range in Covina |
|---|---|
| Room-to-ADU Conversion (all-in) | $85,000 - $140,000 |
| Interior JADU (all-in) | $75,000 - $125,000 |
| Electrical subpanel and circuiting | $4,500 - $8,500 |
Will the price change once work starts?
No. Under Haven Standard Clause 1, your written price is locked at contract signing; if we missed a condition, we absorb it. Call (657) 286-7915 for an exact quote - estimates are free.
Do I need a separate meter for a JADU?
Not always - Covina allows submetering for JADUs under certain configurations, though separate meters simplify rental accounting. We determine the optimal approach during feasibility and price it into your written quote.
ADU Site Prep & Utilities in Covina
ADU Site Prep & Utilities in Covina addresses the hidden infrastructure that makes or breaks every project in this city: the 100-amp panels, the galvanized supply lines, the uninsulated garage slabs, and the SCE upgrade queue that stalls timelines when contractors file late. We front-load this work - submitting electrical upgrade requests concurrent with permit applications - so the critical path stays intact. ADU Site Prep & Utilities is priced as a line item in every design-build contract, never buried in contingencies.
Electrical Panel Upgrade
Signs you need it
Your main panel is rated at 100 amps, has no open breaker spaces, or still uses fuses - all common in Covina’s 1950s-60s housing stock.
What it costs in Covina
Electrical panel upgrades in Covina typically run $8,500-$18,000, including the 200-amp panel, new mast and weatherhead, and SCE coordination.
How we do it
We file the SCE upgrade request simultaneously with your Covina permit application, schedule the utility disconnect-reconnect window, and install the new panel with dedicated circuits for the ADU subpanel.
Foundation & Grading
Signs you need it
Your existing garage slab is 4 inches thick without a moisture barrier, shows cracking or settlement, or sits below the finished floor elevation required for ADU occupancy.
What it costs in Covina
Foundation and grading work for ADU projects in Covina typically costs $12,000-$28,000, ranging from slab reinforcement to full replacement with proper drainage.
How we do it
We assess the existing slab’s compressive strength, design a retrofit or replacement that meets CBC Section 1808 for habitable space, and coordinate the grading plan with Covina’s stormwater requirements.
What ADU Site Prep & Utilities Costs in Covina
| Item | Typical range in Covina |
|---|---|
| Electrical Panel Upgrade (to 200A) | $8,500 - $18,000 |
| Foundation & Grading | $12,000 - $28,000 |
| Plumbing Lateral (new or replacement) | $6,500 - $14,000 |
How long does the SCE upgrade take?
6-10 weeks from request to final reconnect in this SGV service area, which is why we file concurrently with your Covina permit application - never after. Call (657) 286-7915 to schedule your free estimate.
Can site prep be done under a separate contract?
We don’t recommend it - separating site prep from the ADU build creates coordination gaps and voids the 365-Day Done Right Promise, which requires single-contract accountability.
Brands We Service in Covina
We specify and coordinate prefab and modular systems from Plant Prefab, Tuff Shed, and James Hardie within our single-contract design-build model, sourcing components through regional distributors with typical turnaround of 4-8 weeks depending on specification. See our brands for full compatibility details.
Pricing for ADU in Covina, CA
| Service | Typical range in Covina |
|---|---|
| Room-to-ADU Conversion | $85,000 - $140,000 |
| Interior JADU | $75,000 - $125,000 |
| Electrical Panel Upgrade (200A) | $8,500 - $18,000 |
| Foundation & Grading | $12,000 - $28,000 |
| Plumbing Lateral | $6,500 - $14,000 |
| Gas Line Extension | $3,500 - $9,000 |
| HVAC (ductless mini-split) | $4,000 - $8,500 |
| Landscaping & Hardscape (post-build) | $5,000 - $18,000 |
Prices in Covina push toward the higher end when SCE upgrades require trenching, when existing galvanized plumbing needs full replacement, or when summer heat loads demand oversized mini-split capacity. Every figure above is paired with our written-price guarantee under Haven Standard Clause 1: the number you sign is the number you pay.
Neighborhoods We Serve in Covina
We work across Covina’s full residential grid, from the original downtown-adjacent tracts to the post-1965 expansion areas near the city limits. Most projects fall within these representative neighborhoods:
- Downtown Covina
- Covina Hills
- Charter Oak
- South Covina (near Cypress Street corridor)
- North Covina (adjacent to Via Verde)
Dispatch and scheduling are coordinated from our Los Angeles office; crews typically arrive within a scheduled two-hour window.
Service Area - Cities Near Covina
Our crews work throughout the eastern San Gabriel Valley and adjacent communities. Homeowners in West Covina, CA face similar post-war housing stock and SCE upgrade timelines, while Baldwin Park, CA and La Puente, CA share the inland climate conditions that drive HVAC specifications. Glendora, CA to the north has a slightly older housing base with more variance in original electrical service. We price and permit in each city under the same single-contract model.
Serving Covina, CA - Our Local Coverage Area
We’re based in the Covina 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 Covina
Covina’s Community Development Department typically completes plan check in 4-6 weeks for standard ADU applications, faster than LA County’s unincorporated queue. We protect this timeline by submitting a complete permit set and SCE upgrade request simultaneously.
California law (AB 670 and SB 478) prohibits HOAs from outright banning ADUs, but design guidelines and architectural review requirements still apply in Covina’s covenant-controlled neighborhoods. We review your CC&Rs during feasibility and design to the stated standards.
We pull all permits as the licensed design-build entity; the permit is in our name, and we coordinate all inspections. You receive copies of every approved document and inspection sign-off for your records.
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 Covina Customers Say
"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."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."Handled the whole planning process. We went to one hearing and that was it."
- Rowena C.