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Licensed & insuredCSLB #1083621
Permits handledSubmission through final inspection
Founder-ledJoseph and Didi Sheiner on every project
Completed detached ADU on a San Diego lot built by Sheiner Construction Garage conversion ADU in San Diego by Sheiner Construction

San Diego ADU Construction Means Knowing Which Rules Actually Govern Your Lot

ADU construction in San Diego is governed by whichever jurisdiction owns your parcel — not one universal set of rules.

An accessory dwelling unit — a separate living space built on the same lot as a primary residence — sounds straightforward until you start pulling permits. The City of San Diego, Carlsbad, El Cajon, and unincorporated San Diego County each operate under distinct ADU ordinances. A homeowner in one zip code may qualify for a 1,200 sq ft detached ADU with a 4-foot rear setback. A neighbor two blocks away, sitting in a different jurisdiction, faces different size limits, different height standards, and a different review process entirely.

Sheiner Construction builds detached ADUs, attached units, and garage conversion ADUs across the greater San Diego area. Before any design work begins, we verify which ordinance applies at the parcel level — so the unit you design is the unit that gets approved.

CSLB License #1083621. Joseph Sheiner, Founder. Serving greater San Diego since 2012.

A Downtown San Diego Office Serving ADU Projects Across Four Jurisdictions

Direct permit experience across multiple San Diego-area jurisdictions makes a real difference on ADU projects.

Our office is at 1080 Eighth Ave in downtown San Diego. From there, we manage ADU projects across the City of San Diego, Carlsbad, El Cajon, and surrounding communities — each with its own Development Services department, its own plan check timeline, and its own interpretation of where California state ADU law ends and local ordinance begins.

Here's what many San Diego homeowners don't realize about ADU permitting: the state ADU laws — including AB 68 and SB 9 — set a floor. They define the minimum protections cities must extend to ADU applicants. San Diego's local ordinances add provisions on top of that floor. A homeowner who designs to state minimums sometimes submits drawings that fail plan check because a San Diego-specific setback or height standard wasn't accounted for.

We know how those differences play out across jurisdictions because we work in all of them. That working knowledge comes from active permit management across the greater San Diego area, project by project.

How a Single Jurisdiction Line Changed the Entire Design

The ordinance that governs your parcel determines what you can build — not the ordinance your neighbor is under.

I'm Joseph Sheiner. I've been managing ADU projects across San Diego since 2012, and one scenario comes up more than any other: a homeowner arrives with a design roughed out before anyone verified which jurisdiction applied to their parcel.

One project that stays with me started in a neighborhood sitting right on the boundary between City of San Diego territory and unincorporated county land. The homeowner wanted a detached ADU in the back of their lot. Their neighbor had just finished a 900 sq ft unit with what looked like minimal setback from the rear fence. The homeowner assumed the same rules applied to their property.

They didn't.

Their parcel sat inside the City of San Diego. Their neighbor was in unincorporated county. The City's ADU ordinance — Municipal Ordinance MO-21-0001, San Diego's comprehensive ADU framework enacted in 2021 — applied to their lot. The county's ordinance, administered through a separate DSD process entirely, governed the neighbor's.

Before any drawings were produced, I pulled the parcel data and confirmed jurisdiction. The City rules allowed the unit they wanted — but the setback configuration and utility connection requirements differed from what they'd been planning around. We adjusted the placement before a single drawing was committed. The permit went in clean. The unit was approved through the ministerial review process — the non-discretionary track California state law requires for qualifying ADU applications — without a correction cycle.

That's what ordinance verification before design actually buys you. Not just confidence. A permit that moves.

Interior of a finished ADU built by Sheiner Construction in San Diego

What Happens When the Owner-Occupancy Rule Comes Up

California suspended the ADU owner-occupancy requirement through January 1, 2025 — and San Diego cannot reimpose it during that period.

This question comes up on nearly every project. San Diego homeowners who have rental properties, or who are considering an ADU primarily as an income-producing unit, want to know whether they have to live on the lot.

Under California's state ADU preemption, the owner-occupancy requirement was suspended through January 1, 2025. During this period, the City of San Diego cannot require you to live on the property as a condition of building or renting an ADU. Local ordinances that attempt to reimpose this requirement during the suspension period are preempted by state law.

In practice, we confirm the current state of the owner-occupancy rule at the time of your project — because these provisions change, and a rule that was suspended when this page was written may have a different status when your permit is submitted. We verify the current rule against your project timeline and document it in writing before design begins.

Converted garage ADU with living space in San Diego

Our Standards for ADU Construction in San Diego

Every ADU we build is permitted, inspected, and closed with a Certificate of Occupancy — no exceptions.

Ordinance verification first.

We confirm which jurisdiction governs your parcel — City of San Diego, Carlsbad, El Cajon, or unincorporated county — before any design work begins. Design follows the rules that apply to your property.

Ministerial permit track.

Qualifying ADU applications are submitted through California's mandated ministerial review process — non-discretionary, code-compliance-only review. We prepare application packages built for clean approval.

Utility connection fees identified upfront.

Utility connection fees — the costs to connect your ADU to city water, sewer, and electrical service — vary by jurisdiction and unit size. We identify the applicable fee schedule before design decisions are locked in.

Licensed specialty trade partners on every project.

Electrical, plumbing, framing, and mechanical work is performed by licensed trade partners, each holding individual California state licenses and their own insurance coverage.

Certificate of Occupancy at close.

The CO — the final inspection approval confirming your ADU meets all code requirements and is legally habitable — is the standard we build to. Every project closes with one.

How ADU Construction Works: From First Parcel Check to Final CO

The ADU build process has four distinct phases — and the permit phase is where projects either move cleanly or stall.

Diagnostics: Parcel, Ordinance, and Feasibility

Before design drawings are produced, we complete a parcel-level review. This covers jurisdiction confirmation, applicable setback and height standards under the governing ordinance, lot coverage calculations, and utility connection requirements. For detached ADUs of 800 sq ft or less in the City of San Diego, reduced rear and side setbacks — sometimes as low as 4 feet — may apply under MO-21-0001. We confirm whether your parcel qualifies.

We also identify unit type eligibility at this stage. A detached ADU is a fully separate structure built on the same lot as the primary residence. A garage conversion ADU converts an existing attached or detached garage into habitable space — San Diego allows these without requiring replacement parking in most cases, making them one of the more cost-effective ADU paths available in the city. A Junior ADU (JADU) is a unit of up to 500 sq ft created within the walls of the primary residence and carries its own rules distinct from standard ADUs.

Typical timeline from parcel check to permit submittal: 4-8 weeks, depending on design scope and revision cycles.

Implementation: Permit Submission Through Construction

Once the design is finalized against the applicable ordinance, we submit the permit application package to the relevant Development Services department. For qualifying ADU applications in the City of San Diego, ministerial permit approval — the non-discretionary review process California state law mandates — means DSD reviews for code compliance only. Design, aesthetics, and neighborhood character are not grounds for denial.

Construction follows the approved permit set. Licensed specialty trade partners handle electrical rough-in, plumbing connections, framing, and mechanical systems. Each phase is coordinated against the inspection sequence required by the governing jurisdiction.

Post-Construction: Inspections and Certificate of Occupancy

San Diego ADU projects move through a staged inspection sequence — foundation, framing, rough-in trades, insulation, and final — with each stage requiring approval before the next phase proceeds. The final inspection produces the Certificate of Occupancy. The CO is the document that legally confirms your ADU is habitable and compliant. We provide you with a copy at project close.

Realistic permit-to-CO timeline for a San Diego ADU: 4-8 months, depending on project complexity, jurisdiction, and inspection scheduling.

Jurisdiction Comparison at a Glance

FactorCity of San DiegoCarlsbadEl CajonUnincorporated County
Governing OrdinanceMO-21-0001Carlsbad Municipal CodeEl Cajon Municipal CodeCounty ADU Ordinance
Max Detached ADU SizeUp to 1,200 sq ftUp to 1,200 sq ft (state minimum)Parcel-specificParcel-specific
Setback Reduction EligibilityYes — ADUs ≤800 sq ft may qualify for 4-ft rear/sideConfirm per parcelConfirm per parcelConfirm per parcel
Permit Review TypeMinisterial (mandated by state)Ministerial (mandated by state)Ministerial (mandated by state)Ministerial (mandated by state)
Parking Replacement Required (Garage Conversion)No, in most casesNo, in most casesConfirm per parcelConfirm per parcel
Plan Check DepartmentSan Diego DSDCarlsbad Building DivisionEl Cajon Building & SafetyCounty DPW

Rules change. Confirm current standards at the parcel level before committing to a design.

Start Your San Diego ADU With the Right Parcel Check

Your ADU project starts with ordinance verification — so the design you commission is the design that gets approved.

Call Sheiner Construction at 619-577-3749 or email i@sheinerconstruction.com to start with a parcel-level review. We confirm which jurisdiction governs your property, which unit types you're eligible for, and what the utility connection requirements look like — before any design fees are committed.

Start the conversation Call 619-577-3749

CSLB License #1083621. Founded 2012. Office at 1080 Eighth Ave, San Diego, CA 92101.

Greater San Diego ADU Projects — Neighborhoods and Communities We Serve

Sheiner Construction serves ADU projects across the greater San Diego area, from coastal communities to inland jurisdictions.

We build in the City of San Diego — including Mission Hills, North Park, Kensington, City Heights, and surrounding neighborhoods — as well as Carlsbad, El Cajon, Del Mar, La Mesa, Santee, and other communities throughout the greater San Diego region. If your parcel is in greater San Diego, we can confirm which ordinance applies and whether your lot supports the unit you want to build.

  • City of San Diego
  • North Park
  • Mission Hills
  • Kensington
  • Normal Heights
  • Golden Hill
  • Del Mar
  • La Jolla
  • Carlsbad
  • El Cajon
  • La Mesa
  • Santee