In Clyde Hill, One Permit Application Rewrote the Rules on Your Second Home

A developer filed a routine-looking building permit application in Clyde Hill sometime before last November. The plan called for two "cottage homes" on a single residential lot, each with a gross floor area of about 5,000 square feet. On paper, this was legal. Washington's 2023 middle housing law required Clyde Hill to allow exactly this kind of second unit, and the city had adopted its compliance ordinance five months earlier. Two houses on one lot where there used to be one.

The application also read like a loophole, and the City Council treated it like one. On November 10, 2025, the council voted 4-0 to pass an emergency interim zoning control that capped cottage housing at 1,500 square feet, plus 400 square feet for a garage. The change took effect immediately, before the pending permit could vest under the old rules.

If you're weighing a large lot in Clyde Hill against comparable lots in Medina, Kirkland, or Bellevue, this sequence matters more than any single square-footage number. The cap was adopted less than a year ago, was written in direct response to one specific permit, and was structured from the start as a six-month emergency measure rather than a permanent rule.

What the state actually required

Washington's middle housing legislation, primarily House Bill 1110, required cities like Clyde Hill to allow at least two housing units on most residential lots by June 30, 2025. A companion law, House Bill 1337, required cities to permit at least two accessory dwelling units per lot in addition to the main house. A third, House Bill 5258, required cities to allow unit lot subdivision so those extra units could be sold separately rather than only rented.

Clyde Hill's council chose cottage housing as its middle housing type. The ordinance adopted June 10, 2025 allows two cottage homes, or up to two ADUs of 1,000 square feet each plus one single-family home, on most residential lots. Before that, a Clyde Hill property could carry one house and a single 900-square-foot ADU. The city's own housing page frames the update as balancing state compliance against "a majority of Clyde Hill residents" wanting to preserve the existing look of the neighborhood.

What the state law does not require is that a city offer every middle housing type. Nine types exist under the legislation, including duplexes, stacked flats, and courtyard apartments. Clyde Hill picked one. Cottage housing became the only form of middle housing permitted anywhere in the city, which means the size of that single category carries more weight in Clyde Hill than it would in a city offering several parallel paths to added density.

The meeting that reset the number

The emergency ordinance that followed was explicit about what triggered it. City staff wrote that a developer had applied to build two cottage units at roughly 5,000 square feet each on a single lot, and the council found that "immense homes at this scale do not meet the intent of cottage housing and frustrate, rather than serve" the state's affordability goals. The city used its emergency authority to make the change effective on passage rather than after the standard notice period, which is what let it apply before the pending permit could lock in under the June rules.

Planning Commission chair Mark Kroese described the sequence plainly at the meeting. Someone applied to put two 5,000-square-foot homes on a lot, and the discussion turned to whether that fit "the character of our neighborhood," according to reporting from The Urbanist. Councilmembers Dean Hachamovitch and Steve Sinwell, who sponsored the change, told residents in an email that the goal was to align the code with the legislature's original intent for middle housing to serve attainable housing, not to functionally double a large single-family home's square footage under a different label.

Here is what changed, in sequence:

Two rule changes in five months on the same category of construction. That pace, not the specific number, is the detail worth carrying into a lot evaluation.

Two paths, and only one got capped

A buyer thinking about a Clyde Hill lot for a parent, an adult child, or rental income has two distinct routes under the current code, and they were not touched equally.

The cottage housing path, which lets you build two smaller freestanding homes sharing common open space instead of one house, is now capped at 1,500 square feet per unit. That's a modest three-bedroom footprint, not a substantial guest house.

The ADU path is separate and wasn't part of the emergency ordinance. A lot can still carry one single-family home plus up to two accessory dwelling units, attached or detached, at up to 1,000 square feet each. If your interest in a Clyde Hill lot is a detached unit for aging parents or a home office with a bathroom, that ceiling hasn't moved since June 2025.

Anyone evaluating a lot for its added-unit potential needs to ask which path a seller or builder is describing. "Middle housing is legal here now" is true and incomplete. The specific type matters, and in Clyde Hill, only one of the two available types just got smaller.

Why "interim" is the operative word

The November ordinance was built to be temporary from day one. Washington law required the city to hold a public hearing on the interim zoning control within 60 days of passage, and the ordinance's emergency status was tied to a roughly six-month window, meaning that window would have closed around the spring of 2026. What happens at the end of that window is either the council adopts the cap as a permanent standard through the normal process, revises it, or lets it lapse back to the June 2025 rule. Nothing in the reporting on the original vote settles which of those happened, which means the 1,500-square-foot figure should be confirmed directly with the city rather than assumed to still be current.

There's a second layer of uncertainty worth naming. The Urbanist's coverage points out that HB 1110 bars cities from imposing "any standards for middle housing that are more restrictive than those required for detached single-family residences," and a size cap that applies only to cottage units, while leaving single-family construction unrestricted by that same ceiling, is the kind of provision that could draw a legal challenge on exactly those grounds. Separately, as of mid-2025 Futurewise, a land-use advocacy group, had a complaint pending against the city over its broader density regulations, according to a council member's own newsletter recapping the group's July update. Neither of these resolves the current number on its own. Both are reasons to treat whatever figure the city quotes you as provisional rather than settled law.

What this means if you're looking at a large lot here

The headline version of Washington's middle housing law suggests every qualifying lot in the state gained meaningful new building rights in 2025. In Clyde Hill, the practical version is narrower than that headline implies. A size cap on cottage homes isn't unusual on its own. Kirkland and Medina both have similar caps in place. What sets Clyde Hill apart, per the Urbanist's reporting, is the combination: cottage housing as the only middle housing type offered, now capped tightly enough that the city's overall code reads as one of the most restrictive implementations of HB 1110 in the state.

For a buyer comparing a large Clyde Hill parcel against a similarly sized lot in a neighboring city, the redevelopment math should start from what's actually buildable, confirmed with the city at the time of the offer, not from the assumption that state reform opened the same door everywhere at the same width. A 20,000-square-foot lot here supports a second dwelling. Whether that dwelling is capped at 1,500 square feet, some revised number, or reverted to the broader June 2025 standard is a fact that changed once already within five months of the original ordinance, and it is worth re-confirming rather than assuming.

A few questions worth asking before you write an offer

Does the cottage cap affect a lot where I'd only want one ADU for a family member? No. The two-ADU path, capped at 1,000 square feet per unit, was part of the June 2025 ordinance and wasn't altered by the November emergency ordinance.

Is the 1,500-square-foot cottage cap likely to change again? It's an interim measure with a required public hearing and a limited effective period built into how Washington law treats emergency zoning actions. Confirm the current status with the city before treating any specific number as long-term.

Does this change what a large Clyde Hill lot is worth? It changes what you can build on it, which is a component of value, not the whole of it. A property's price should reflect the buildable envelope in effect at the time of your transaction, confirmed directly with the city rather than assumed from the general middle housing headlines.

If you're comparing a Clyde Hill lot against options in Medina, Kirkland, or Bellevue and want the current buildable picture before you write an offer, James Campbell can walk through what each city's code allows today. Let's Connect.