Now that Mayor Kirk Caldwell has signed Bill 20 into law, allowing accessory dwelling units in all residential areas, I’ll make a prediction: There are going to be a lot of unhappy homeowners across Oahu when they find out that they won’t be able to take advantage of the new law.

Here’s the problem. News coverage of the debate has focused on the broad coverage of the new bill, which applies to all areas that are zoned residential or country. In all of those areas, accessory units will now be allowed by the city zoning, with some restrictions.

But what wasn’t really clear in the coverage or discussion of the measure is that the change in zoning does not override restrictive covenants that apply in most planned communities, where they are enforced by a developer or a homeowners’ association.

There are six important words, missing in the news coverage, that appear in a new set of frequently asked questions just posted on the website of the Department of Planning and Permitting.

Here’s item #3.

3. Where can I build an ADU?

An ADU can be built on any lot zoned Residential (R-3.5, R-5, R-7.5, R-10, and R-20) or Country District with a lot area of 3,500 square feet (SF) or more provided that there is adequate infrastructure and subject to meeting all other Land Use Ordinance provisions for the zoning lot and there are no restrictive covenants.

Here in Kahala, for example, there are restrictive covenants that trace back to the original Bishop Estate leases in the area. Only single family homes are allowed on each lot, so no accessory units can be added here.

Mililani? Planned community, lots of rules. I’m guessing that most of the growing areas of Ewa and Kapolei are also subject to restrictions. If there’s a list of planned communities, and their community associations, I’m guessing that every place on that list will be off-limits for the new accessory dwelling units. And, further, I predict that homeowners will be blindsided by these restrictions, and will start putting pressure on their association boards to allow ADUs. This is likely to become a new policy battleground in neighborhoods around the island.