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

What you can build on your lot

Everything in this section is grounded in Covina Municipal Code § 17.69.040 and the California Government Code it implements, with state-law citations called out where they supply or override the local rule. We won’t re-cite the Covina section on every line — assume it under each heading unless we tell you otherwise.

Number of ADUs per lot

• Single-family lot. The ordinance frames the allowance as a detached ADU plus a junior ADU. State law is more generous, and it controls: Gov. Code § 66323(a)(1)–(2) requires the City to allow a conversion ADU created from existing space, plus a junior ADU, plus a new detached ADU of up to 800 sqft — up to two ADUs and a JADU on one lot. We cover the preemption in the state-law section below.
• Multifamily lot — existing building. Conversion ADUs in non-livable space — at least one, up to 25% of the existing units — plus detached ADUs. Covina’s text caps detached units at two, but SB 1211 raised the floor to eight detached ADUs on a lot with an existing multifamily building, not to exceed the number of existing units (Gov. Code § 66323(a)(3)–(4)). State law controls.
• Existing accessory structures. A detached accessory structure may be converted to an ADU — an old workshop or oversized garage can become a unit without being held to the new-construction size limits.

Size limits

• Detached ADU: up to 1,000 sqft — generous for a single-story market and matched exactly by our single-story flagship, the 1,000 sqft Lincoln.
• Attached ADU: up to 50% of the existing primary dwelling — but never forced below 800 sqft by that percentage, because state law protects the 800 sqft floor and the 850/1,000 sqft size floors (Gov. Code § 66321(b)(2)–(3)).
• Detached ADU built with a JADU: held to 800 sqft, the by-right detached size in Gov. Code § 66323(a)(2).
• Conversion ADU: no separate square-foot cap when created within existing permitted space; a converted accessory structure may add up to 150 sqft for ingress and egress (Gov. Code § 66323(a)(1)).
• Junior ADU: up to 500 sqft inside the single-family home (Gov. Code § 66313(d)) — created within the walls of the home, so the 150 sqft ingress/egress allowance for accessory-structure conversions does not apply.
• Design standards over 800 sqft. An ADU larger than 800 sqft must meet the City’s adopted ADU design standards — objective standards a plan checker applies, not a discretionary review.

Setbacks

Side and rear setbacks are 4 feet for a new single-story ADU — matching the state-law floor in Gov. Code § 66314(d)(7) — and the front setback follows the underlying zoning district. No added setback is required for an ADU built within an existing structure, whether a conversion or a same-footprint replacement. On a typical Covina parcel the practical move is to set the unit in the rear yard and let the 4-foot envelope do the work.

Maximum height — single story by right

A detached ADU in Covina is capped at 16 feet when it sits at the 4-foot side and rear setback (Gov. Code § 66321(b)(4)(A) sets that same 16-foot floor statewide). A unit taller than 16 feet — a two-story detached ADU, or a second story above a garage — is allowed only where it fits inside the primary residence’s buildable area, as determined under the City’s residential development standards (CMC §§ 17.14, 17.26). In plain terms: for a standard backyard ADU at the 4-foot envelope, Covina is a single-story market. Our three two-story Signature Homes — the Fairfax, Venice, and Culver — are detached designs that need roughly a 25-foot detached envelope, so they generally do not fit Covina’s by-right detached envelope. We say that plainly because it shapes the plan: on a Covina lot the right move is one of our six single-story models, and the City’s 1,000-square-foot detached cap is roomy enough to put a full three-bedroom single-level home in the back yard. The detail on the buildable-area path is in the next section.

Parking

Covina requires one off-street parking space for an ADU — unless the lot is within one-half mile of public transit, measured by walking distance from the unit, in which case no parking is required. That tracks the state framework, which lets a city ask for up to one space per ADU and then waive it in a list of situations, including transit proximity (Gov. Code § 66322). A junior ADU never requires parking (Gov. Code § 66334(a)), and when a garage, carport, or covered space is demolished or converted for an ADU, those spaces never have to be replaced (Gov. Code § 66314(d)(11)). Reading your lot’s distance to a transit stop early tells you whether the parking space is even on the table.

Lot coverage, FAR, and open space

The underlying zone’s floor-area-ratio, lot-coverage, and open-space limits still apply to an ADU, but every one of them is expressly subject to the 800-sqft floor: none may force an ADU below 800 square feet (Gov. Code § 66321(b)(3)). On Covina’s deeper single-family lots these rarely bind a backyard unit, and where a tighter parcel comes into play, an 800-sqft unit is still protected.

Owner-occupancy

Covina does not require the owner to live on the property for an ADU — the ordinance imposes no owner-occupancy requirement on an ADU, matching Gov. Code § 66315, which bars it statewide. The ordinance still requires the owner to occupy either the junior ADU or the primary dwelling for a JADU (unless the owner is a government agency, land trust, or housing organization), recorded by covenant, but that language predates AB 1154. Effective January 1, 2026, AB 1154 amended Gov. Code § 66333(b) so JADU owner-occupancy applies only when the JADU shares sanitation facilities with the primary dwelling. Because Covina adopted Ordinance 22-06 in May 2022, the local text is operatively behind the state rule — a JADU with its own dedicated bathroom carries no owner-occupancy mandate. We cover this in the state-law section below.

Recorded covenant

Covina requires a recorded covenant agreement for every ADU and JADU (Ordinance No. 22-06). It runs with the land and records the unit’s approved terms — the 30-day-or-longer rental restriction, the bar on separate sale, and, for a JADU, the size limit and any applicable owner-occupancy condition. It is a routine recordation handled at permit clearance, not a discretionary hurdle, and we prepare it as part of the permit package.

Impact fees and utility connections

No development impact fee may be charged on an ADU under 750 sqft, and state law exempts ADUs of 750 sqft or less outright (Gov. Code § 66311.5(c)). Above that threshold, impact fees are charged proportionally to the primary dwelling’s square footage — the ADU’s floor area divided by the primary’s, times the usual fee — not a flat per-unit charge. An ADU generally relies on the primary dwelling’s existing utility connections; where a separate connection is required, the connection and capacity charge are priced to the burden the unit actually adds.

Permitting timeline

ADU and JADU applications are reviewed ministerially — no public hearing, no discretionary design review, no neighbor sign-off (Gov. Code § 66317). The City must approve or deny a complete application within 60 days or it is deemed approved. SB 543 (effective January 1, 2026) adds a written completeness determination within 15 business days (Gov. Code § 66317(a)(2)).

How California state law overrides Covina

Covina’s ordinance is generous on size, but on a few points it still reads more narrowly than current state law. Under Gov. Code § 66316 the state standard controls wherever the local text is narrower — here are the places that matters for your plan.

• You can build more than a detached ADU plus a JADU. The ordinance describes the single-family allowance as a detached ADU and a junior ADU. State law requires the City to allow the full stack: a conversion ADU from existing space, plus a junior ADU, plus a new detached ADU of up to 800 sqft — up to two ADUs and a JADU on one single-family lot (Gov. Code § 66323(a)(1)–(2); HCD ADU Handbook, March 2026, pp. 17–18). The narrower local reading is preempted.
• Multifamily lots can hold up to eight detached ADUs. The ordinance caps detached ADUs at two on a multifamily lot. SB 1211 raised the floor to eight detached ADUs on a lot with an existing multifamily building, not to exceed the number of existing units (Gov. Code § 66323(a)(4)). The two-unit cap holds only where the multifamily building is merely proposed.
• Junior-ADU owner-occupancy is narrower than the local text. The ordinance requires owner-occupancy for a JADU. AB 1154 amended Gov. Code § 66333(b) effective January 1, 2026 to require it only when the JADU shares a bathroom with the main home. Covina’s ordinance was adopted in 2022, years before that change, so a JADU with its own dedicated bathroom carries no owner-occupancy mandate.
• The 800-sqft floor beats local coverage and FAR rules. An 800-sqft ADU at 16 feet with 4-foot setbacks must be approved regardless of lot-coverage, floor-area-ratio, or open-space limits (Gov. Code § 66321(b)(3)) — useful certainty on a tighter parcel.
• No owner-occupancy for an ADU, and no replacement parking. Gov. Code § 66315 bars an ADU owner-occupancy requirement statewide, and Gov. Code § 66314(d)(11) bars requiring replacement parking when a garage is demolished or converted for an ADU. Covina’s ordinance already reflects both — confirmation, not conflict.

Renting an ADU in the San Gabriel Valley

Plan a Covina ADU around 30-day-or-longer tenancy. The City requires that an ADU be rented for a term longer than 30 days (Covina Municipal Code § 17.69.040) — the 30-day minimum state law lets a city set (Gov. Code § 66323(e)). Nightly and weekly short-term rental is out; the compliant model is a long-term lease or a furnished mid-term rental — corporate, traveling-medical, or academic tenants.

The benchmark worth anchoring to: HUD’s Fair Market Rents for the Los Angeles–Long Beach–Glendale metro area, revised effective May 21, 2026, put a one-bedroom at $2,328, a two-bedroom at $2,903, and a three-bedroom at $3,681 per month (FY 2026 FMRs, huduser.gov; 91 Fed. Reg. 21301). A newly built ADU with in-unit laundry and a private entrance typically rents at or above those figures — and Covina’s 1,000-square-foot detached cap reaches a full three-bedroom single-level home, which lands in the three-bedroom band. Covina’s rental drivers are durable: established single-family neighborhoods, a deep San Gabriel Valley multigenerational housing culture, Metrolink and bus access from the historic downtown, and steady demand from nearby Citrus College and the SGV job corridor.

For payback math keyed to your lot and financing assumptions, use the ADU ROI calculator.

Newly constructed ADUs first occupied after February 1, 1995 are generally exempt from California rent-ceiling controls under the Costa-Hawkins Rental Housing Act (Civ. Code § 1954.50 et seq.). The statewide rent-cap framework under AB 1482 (Civ. Code § 1947.12) may still apply depending on the ADU’s structure and ownership — confirm before you lease.

HUD Fair Market Rents are a federal benchmark for the metro area, not a guarantee of what your unit will rent for. Actual performance depends on finish level, lot, access, parking, and the rental market when you lease.