Glendale Refused an SB 9 Duplex Because the Lot Already Had an ADU

You own a single-family lot in California. There's a house on it, and a backyard ADU you added a few years ago. Now you want to add a second primary dwelling under SB 9 — the state's two-unit law. You file the application, and the city writes back before it will even invoice the fees: your lot is ineligible, because it already has two units.

Here's the thing: the "second unit" the city is counting is your ADU — and HCD's position is that an existing ADU doesn't count against the SB 9 two-unit cap unless you're also splitting the lot.

What happened in Glendale

An applicant at 1316 North Pacific Avenue ran into exactly this. The lot had one single-family dwelling and one ADU, and it had never been subdivided through an SB 9 urban lot split. The applicant tried to submit application PSB9-004777-2025 to add a second primary dwelling under Government Code § 65852.21 — the two-unit "duplex" half of SB 9.

The City of Glendale wouldn't process it. In an April 11, 2025 email, the City told the applicant:

"…the property is currently ineligible for an SB 9 housing development."

That's the City's line, not HCD's. Glendale's theory rested on its own code — GMC 30.34.110(D)(2) and 30.34.110(C) — which caps an SB 9 development at two units and defines "unit" broadly enough to sweep in ADUs and JADUs. On that reading, the house plus the existing ADU already hit the cap. The City told the applicant the only path forward was to file a lot split too:

"If an additional unit for the existing property is desired, then a concurrent SB 9 lot split application is required to be submitted in addition to PSB9-004777-2025. This concurrent application would allow up to four units (two existing and two SB 9 units) to be developed on the lot as it currently exists."

Note what the City did here: it refused to accept or consider the application — it never formally denied it.

Where HCD says the City went wrong

HCD issued a Letter of Technical Assistance to Glendale on February 10, 2026, and its position turns on a single word: section.

The two-unit cap and the broad definition of "unit" that pulls in ADUs and JADUs both live in Government Code § 66411.7 — the urban lot split half of SB 9. That cap says a local agency "shall not be required to permit more than two units on a parcel." HCD's point: that limit applies only to § 66411.7, the lot split provision — not to § 65852.21, the standalone two-unit provision.

"…a local agency shall not be required to permit more than two units on a parcel…"

So when a project uses only § 65852.21 and does not involve a lot split, HCD's position is that the city can't borrow § 66411.7's unit cap to block it. In the letter's words, a local agency "must apply ADU law independently and cannot impose a two-unit cap that includes ADUs or JADUs."

The practical upshot for this lot, as HCD states it:

"The subject property, currently containing one primary dwelling and one ADU, is eligible to apply to construct one additional primary dwelling under SB 9 and additional ADUs under ADU Law."

One house, one existing ADU — and still room for a second primary unit plus more ADUs, because no lot split is in play.

Verified against HCD's Letter of Technical Assistance to the City of Glendale (February 10, 2026), regarding 1316 North Pacific Avenue.

What HCD asked for — and why it isn't the final word

HCD directed the City to accept and process the application, and to fix its code: "the City must amend the Glendale Municipal Code so that sections 30.34.110(D)(2) and 30.34.110(C) comply with SB 9 and SB 450." It asked for a written response by March 9, 2026.

This one has teeth because Glendale pushed back. HCD noted the City "disagreed with HCD's interpretation of the relevant statute and expressed its intention to continue to implement the law consistent with its own interpretation."

That standoff shapes how you should use this. An HCD technical-assistance letter is HCD's interpretive position, not a court ruling — and here the recipient city openly disagrees with it. It's a strong signal that a barrier you're hitting may be unenforceable, but it isn't settled law. If your city is counting an existing ADU against an SB 9 two-unit project where no lot split is involved, this is worth raising — then verify with your planning department or land-use counsel before you rely on it. None of this is legal advice.

What CrossBeam does with it

When the letter lands on your desk, CrossBeam turns it around the same day: what each item is actually asking, the code or law behind it, and a written response you can hand to your team or your attorney — the back-and-forth that used to eat weeks, done in a couple of hours.