GR ADU Zoning Update

On Tuesday, June 16, 2026, the Grand Rapids City Commission adopted an updated ADU ordinance at their “Night Out at the Museum” meeting. The headline change: ADUs can now be up to 1,000 square feet, as long as the primary structure is at least 1,000 square feet — an increase of at least 20% over the previous max, which was usually funtionally 832 square feet (though that number was variable and confusing).

They also removed the previous two-bedroom maximum.

The intent was to simplify the ordinance and recognize that it’s a better build to have the staircase inside the building envelope. If a staircase takes up 100 square feet and your maximum is 832, you’re “wasting” 12% of your usable space, which is why many people have been building staircases on the exterior, so they’re considered “decks.” Decks complicate things, though, because the ordinance doesn’t allow them to be built too close to side setbacks. Folding the staircase back into the building envelope avoids that issue: the building code allows stairs to sit as close as 3 feet to the property line and still include windows.

You can read the excerpt from the City Commission agenda packet here.

Here’s what the old F. Floor Area section said:

Here’s what the old F. Floor Area said:

1. The maximum permitted floor area for an accessory structure that contains a second-floor ADU may be increased by one hundred (100) percent solely for the construction of a second-floor unit.
2. Maximum ADU Size. The ADU shall not exceed forty (40) percent of the gross floor area of the primary structure or four hundred (400) square feet, whichever is larger. In no case shall the ADU exceed eight hundred fifty (850) square feet in gross floor area.

Here’s what it’s being updated to say:

1. An ADU is not subject to the maximum gross floor area for accessory structures in Section 5.2.08.
2. Maximum ADU Size. An ADU shall not exceed one thousand (1,000) square feet. In no case shall an ADU exceed the gross floor area of the primary structure.

These are just two ideas generated as part of the Mayor’s ADU Task Force. It’s a bit disappointing that six months of work resulted in implementing only two of the more than 100 recommendations, especially since neither recommendation materially changes the economics of building an ADU.

When the Planning Commission was advancing these recommendations several months ago, I made a public comment to them about the two recommendations that would actually move the needle economically: allowing two ADUs per lot, and allowing short-term rentals. Since a large portion of an ADU’s build cost is tied to utility connections, having two units would let builders split that cost across two units instead of forcing one small unit to absorb it all. Short-term rentals are a hot topic, and that ordinance would have sparked plenty of debate, but the underlying policy logic holds: over time, a meaningful share of short-term rentals convert to medium or long-term rentals, simply because running an Airbnb is a lot of ongoing work. And because we’re talking about new construction, none of it comes at the expense of existing housing stock. It would let many units get built, and over time, a portion of them would convert into longer-term housing. In the meantime, the higher short-term rental income would help offset the high cost of building.

It’s difficult to change policy once it’s already moving from the Planning Commission to the City Commission, and in this case, the Commission chose to advance the Planning Staff’s recommendations as written, without requesting any changes.

If you’re interested in reading the full ADU Task Force Recommendations, it’s available here. There’s even a picture of me working with the team!