Building an ADU in Lomita. Rules, costs, timeline.

Can I build an ADU in Lomita?

Five things to know before you start

If you read nothing else on this page, read these. They are the five points that change the most projects in this city.

How many units your lot can take

Everything in this section is grounded in LMC § 11-1.30.07 as enacted by Ordinance No. 891, and in Gov. Code § 66323; we will not re-cite the local section on every line. The short version is that Lomita now writes the state unit stack into its own code rather than leaving homeowners to argue for it.

Subsection (E)(1)a gives a single-family lot one ADU converted from existing space in the house or an accessory structure, plus one JADU of up to 500 sqft. Subsection (E)(1)b gives it one new detached ADU of up to 800 sqft of livable space with 4-foot side and rear setbacks. The ordinance then says in its own text that the two paragraphs may be combined. That is two ADUs plus a junior ADU — exactly the combination Gov. Code § 66323(a)(1)–(2) requires, and the combination the HCD ADU Handbook (March 2026), p. 17, works through as its example.

On a lot with an existing multifamily building, (E)(1)c allows conversion of non-livable space into at least one ADU and up to 25% of the existing unit count, and (E)(1)d allows up to eight detached ADUs, capped at the number of primary dwelling units on the lot (Gov. Code § 66323(a)(4)(A)(ii)). A lot with a proposed multifamily building gets two. Those two paragraphs may be combined as well. JADUs remain a single-family product.

Owner-occupancy

You do not have to live on the property to build or rent an ADU in Lomita. Subsection (F)(7)a says so outright: ADUs are not subject to an owner-occupancy requirement. That matches Gov. Code § 66315, which forbids a city from imposing one. The older City handout that described the requirement as waived only until January 1, 2025 has been overtaken by the code, and the preemption question it raised is closed.

What an ADU costs in Lomita (2026)

Our Signature plans are fixed-price. Architectural design and full permit processing are included, and it is the same number whether the lot sits north or south of Pacific Coast Highway. Construction is separate. Once your plans are permitted, you build it yourself, bring your own licensed contractor, or build with one of our vetted construction partners. The figures below are the estimated cost to build each model with an independent licensed general contractor.

The two-story models are shown for reference. In Lomita the detached envelope is a single story, so the Lincoln at 1,000 sqft is the ceiling as drawn — and it lands exactly on the local size cap for a two-bedroom-or-larger unit. Custom work is priced per project, $9,990–$19,990 for design and permit processing.

City fees and pass-throughs

A conforming ADU in Lomita is a ministerial permit, so there is no planning entitlement to buy. What you pay is the City’s valuation-based building-permit and plan-check charge, plus any utility connection where the unit takes its own service. We do not publish a dollar figure for those here. Lomita’s fee schedule is adopted by resolution and revised periodically, and the schedule that was current before Ordinance No. 891 was written against a different permit structure. A stale number is worse than no number. Confirm the current figures with the Planning Division.

Three things are settled and worth banking. Subsection (H)(1)a charges no impact fee on a JADU or on an ADU with less than 750 sqft of interior livable space, which is what Gov. Code § 66311.5(c)(1) requires. At 750 sqft or more, any impact fee must be proportional to the primary dwelling’s square footage rather than charged flat per unit ((H)(1)c). And a JADU or ADU under 500 sqft is not subject to school fees under Education Code § 17620 ((H)(1)b). The ordinance defines an impact fee narrowly — a Mitigation Fee Act fee (Gov. Code § 66000(b)) and a Quimby Act fee (Gov. Code § 66477) — and expressly excludes water and sewer connection fees and capacity charges from the exemption.

What it returns: renting your ADU

Long-term rental only, so the income to model is a lease rather than a nightly rate. For a benchmark, the government figure is HUD’s Fair Market Rent for the Los Angeles–Long Beach–Glendale HUD Metro FMR Area, which covers Lomita. For FY 2026, as revised effective May 21, 2026: $2,079 for a studio, $2,328 for a one-bedroom, $2,903 for a two-bedroom, and $3,681 for a three-bedroom. Those are metro-wide figures spanning the full range of housing stock and unit ages, so treat them as a floor rather than a forecast. A newly built detached ADU on a quiet Lomita street usually rents above FMR — we would rather point you at a verifiable number than an invented one. A local property manager can price your specific block.

HUD FMR figures: FY 2026 Fair Market Rents for the Los Angeles–Long Beach–Glendale, CA HMFA, as revised by 91 FR 21301 (published April 21, 2026; effective May 21, 2026). Your ADU’s actual performance depends on finish level, lot, access, and the rental market at the time you lease it. For payback math keyed to your lot, use the ADU ROI calculator or the ADU calculator.

When an ADU isn’t the right move

Not every Lomita property is a good ADU candidate, and it is cheaper to learn that now than after you have paid for plans. Four situations where we would tell you to wait, pick a different unit type, or not build:

• Your numbers depend on short-term rental income. They will not work. Subsection (F)(4) sets a 30-day minimum and applies it regardless of when the unit was created, and state law requires that floor rather than merely permitting it. Run the math on a 30-day-plus tenancy or reconsider.
• You want a separate-sale exit. The City has not adopted a Gov. Code § 66342 condominium opt-in, so the ADU cannot be sold apart from the house. If a condominium-style exit is the plan, this is the wrong jurisdiction for it.
• You need two stories of detached space. The ordinance does not offer that route, and the extra-height allowance at (F)(2)f buys height over on-grade parking rather than a second floor of living space. The honest options are a single-story detached unit, an attached two-story unit, or a conditional use permit under (J) — which is discretionary and takes the project out of ministerial review entirely.
• Your lot is already at the coverage or floor-area ceiling. Subsections (G)(2) and (G)(4) cap total floor-area ratio at 60% and, on R-2 and R-3 lots, total coverage at 80%. Those caps cannot shrink you below 800 sqft, but they can rule out the larger 1,000-sqft unit you had in mind. Measure before you design.

The rules that make Lomita different

The Pacific Coast Highway line, and why it is not a coastal boundary

Lomita is landlocked. No part of the city sits in the Coastal Zone, LMC § 11-1.30.07 contains no coastal provision, and no coastal development permit is required for an ADU here. That is worth saying plainly, because the ordinance mentions Pacific Coast Highway and South Bay homeowners reasonably assume the two are connected.

They are not. The line at (F)(2)f(iii) is a local height control. South of PCH, the extra height that (F)(2)f otherwise allows over an on-grade parking podium additionally requires a height variation permit under LMC § 11-1.70.11. North of PCH it does not. Neither side of the line changes anything about the ordinary 16-foot detached envelope, the 4-foot setbacks, the unit counts or the 60-day clock. If you are not asking for extra height over parking, the PCH line does not touch your project at all.

Where the architectural standards stop

Subsection (G)(7) is a genuine design package: matching materials and colors, a roof slope matching the primary dwelling’s dominant slope, down-lights only, a 10-foot minimum interior dimension, a 7-foot minimum wall height, no direct line of sight to an adjoining residential property, and clerestory or obscure glazing within 30 feet of a property line that is not a public right-of-way. On an older Lomita house that is a real constraint on the design, and it is why our traditional gable elevations get picked here.

It is also the part of the chapter with the most exposure. Two of its tests — requiring materials and colors to be “the same as” the primary dwelling, and a “direct line of sight” judgement — use the wording HCD has treated as impermissibly subjective in a parallel chapter elsewhere in the South Bay, measured against the objective-standards requirement in Gov. Code §§ 66313(i) and 66314(b)(1). No HCD letter addresses Lomita’s current text, so we are not telling you the standards are unenforceable. We are telling you where the argument lives, and what you can do without having it.

Where local rules and state law pull apart

After the June 2026 rewrite, most of the old preemption fights are gone: owner-occupancy, unit counts, multifamily counts, parking replacement and the impact-fee exemption are all written into the local text the way state law requires. Two points remain open, and both are open questions rather than settled conflicts.

Renting, selling and the 30-day floor

Subsection (F)(5) lets you rent an ADU or a JADU and bars selling or otherwise conveying it separately from the lot and the primary dwelling — or, on a multifamily lot, separately from the lot and all of the dwellings on it. The one exception the ordinance writes in is Gov. Code § 66341, the mandatory statewide route for a unit built by a qualified nonprofit and conveyed to a qualified low- or moderate-income buyer under a recorded tenancy-in-common agreement. That route needs no local opt-in.

The condominium route is a different statute and it does need one. Gov. Code § 66342 lets a city opt in by local ordinance, and Lomita has not adopted one. Among Los Angeles-area cities only a handful have — Santa Monica (SMMC § 9.31.026) and Culver City (CCMC § 17.400.096) among them. Build here for rental income, family housing or long-term value.

The disaster-rebuild exception

One provision is worth knowing even though most owners will never use it. Subsection (F)(10) normally holds the ADU’s certificate of occupancy until the primary dwelling has one. The exception: a detached ADU may take its certificate first where the county is under a Governor’s state-of-emergency proclamation made on or after February 1, 2025, the primary dwelling was substantially damaged or destroyed by that event, the ADU has permits and has passed all inspections, and the ADU is not attached to the primary. For a family rebuilding after a fire, that turns the ADU into somewhere to live during the rebuild rather than something that waits on it.

Two related items sit in the same subsection and are easy to trip on. Fire sprinklers are required in an ADU or JADU only if they are required in the primary residence, and building one does not trigger a sprinkler retrofit of the existing house ((F)(3); Gov. Code § 66314(d)(12)). And constructing an ADU does not change the building’s Group R occupancy classification absent a written adverse-impact finding ((F)(9)b).