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

What can you build?

Which ADU type fits your property?

Five types are permitted. This is the fastest way to work out which one your lot is pointing you toward.

Size limits

Height

A detached ADU may be 16 feet on a standard single-family lot. Within a half-mile of a major transit stop or high-quality transit corridor that rises to 18 feet, with two further feet available to match your home’s roof pitch. Two stories is the ceiling either way.

An attached ADU may reach 25 feet or the underlying zone limit, whichever is lower. These figures track the state floors at Gov. Code § 66321(b)(4) rather than exceeding them, so Glendale is a tighter envelope than the Westside cities.

Setbacks

Four feet from interior side and rear lot lines is the most the City may require. State law caps ADU side and rear setbacks at four feet, and Glendale's code carries the same cap. A conversion, or a replacement built in the same location and to the same dimensions, needs no additional setback at all.

One trap on a tight lot. For an ADU created within existing space under GMC § 30.34.080.E.4(a), the code treats an existing interior setback of at least three feet as a condition of using that route, for fire safety. It is not a concession in your favor. State law imposes no such number on a conversion unit — Gov. Code § 66323(a)(1) asks only that setbacks be sufficient for fire and safety, and § 66323(b) bars a city from adding objective standards to these units. If your existing setbacks are tighter than three feet, say so and cite § 66323(b) rather than assuming you are out.

Front setbacks follow the underlying zone, subject to Gov. Code § 66321(b)(3), which bars any front-setback rule that would prevent an 800 square foot ADU with four-foot side and rear setbacks from being built.

If you own an apartment building

This is where the gap between Glendale’s code and your entitlement is widest, and it is worth reading carefully.

GMC § 30.34.080.F.2 states that the applicant “is entitled to build accessory dwelling units under either subsection (F)(2)(a) or (F)(2)(b) below, but not both.” Subsection (a) is interior conversions — at least one unit and up to 25 percent of your existing count. Subsection (b) is detached units. The code makes you pick.

Gov. Code § 66323 does not. Subdivision (a)(3) provides the conversions and subdivision (a)(4) provides up to eight detached units on a lot with an existing multifamily building, capped at the number of units already there. They are separate entitlements. HCD challenged Glendale’s either/or rule, and it is one of the provisions the City agreed to stop enforcing.

How long an ADU takes

Both clocks have teeth, and they bite in different ways. If the City misses the 15 business days, your application is deemed complete. If it does send a completeness notice in time, that notice has to list every missing item and how to cure it — and when you resubmit, the City may not demand an item it left off its own list. If it misses the 60 days, the application is deemed approved (Gov. Code § 66317(a)).

The 60-day window covers the whole permitting agency — planning, building and utilities alike. Building plan check happens inside it, not after. A denial must arrive with a full set of comments listing every deficiency.

How the permit process works

Ministerial means a reviewer applies the numbers in the ordinance to your drawings. Design taste, neighborhood opinion and discretion are not part of it.

What you submit

A complete application is the single biggest factor in how long this takes. Expect a site plan, floor plans, elevations, structural drawings, and Title 24 energy documentation. On hillside parcels, add a survey.

The completeness step is bounded. Gov. Code § 66317(a)(2) gives the City 15 business days to decide in writing, with a list of what is missing and how to fix it, and it cannot later demand something it left off that list.

Raising the MOU at the counter

If your project depends on one of the four things the MOU covers, say so early and in writing. Ask for confirmation at pre-application rather than arguing it at plan check.

The City was required by the MOU to announce publicly, at Council and at the Planning Commission, that it would not enforce the challenged provisions. So this is not obscure — it is simply not printed in the code a plan checker reads from.

If you are refused anyway, you are not finished. Gov. Code § 66317(d) requires Glendale to give you a written appeal — on a denial or on an incompleteness determination — running to the City Council or the Planning Commission, with a final written determination within 60 business days. A refusal on one of the four configurations the City has agreed in writing to allow is close to the textbook case for using it.

Unpermitted work already on the property

Old work does not automatically block a new ADU. Under Gov. Code § 66322(b) the City may not deny your application over nonconforming zoning conditions, code violations or unpermitted structures that do not threaten health and safety and are not affected by the ADU you are building.

If the unpermitted structure is itself an ADU or Junior ADU built before January 1, 2020, Gov. Code § 66311.7 is stronger still: generally no denial, no penalties, and no impact fees or connection charges on the legalized unit. Those protections fall away entirely in two cases, so know them before you rely on the section: where the City finds that correcting the violation is necessary to protect the health and safety of the public or the occupants, and where the building is deemed substandard under Health and Safety Code § 17920.3. Glendale has to publish a checklist of the conditions that make a building substandard, and you are entitled to a confidential third-party code inspection before you file anything.

Official sources

Glendale

• GMC § 30.34.080 — Accessory Dwelling Units and Junior Accessory Dwelling Units. Last amended by Ordinance 6034, effective December 3, 2024. View on eCode360
• City of Glendale Community Development — planning counter, submittal information and current bulletins. glendaleca.gov

California

• HCD – City of Glendale Memorandum of Understanding, dated October 3, 2025 — the agreement that governs which provisions the City may enforce. Read the MOU (PDF)
• Gov. Code §§ 66310–66342 — state ADU law, renumbered by SB 477 effective March 25, 2024. leginfo.legislature.ca.gov
• Gov. Code § 66316 — the section under which a noncompliant local ADU ordinance is null and void. leginfo.legislature.ca.gov
• HCD ADU Handbook — the state’s official interpretive guidance. hcd.ca.gov

Rules change, and Glendale’s are actively in flux. The amending ordinance the MOU contemplates had not been adopted when this page was last verified. If you are reading this later, confirm whether Council has acted — or call us and we will confirm it for you.