ADU Reform is one way to address the housing crisis

The housing crisis does not have a single solution. Representatives of Better Boulder, Boulder Is For People, and Boulder Housing Network have been been discussing solutions. There are many policy changes that can individually make small contributions to alleviating the crisis, and if combined, could significantly improve the availability and affordability of housing in Boulder.

We have been meeting to discuss one such policy tool: Accessory Dwelling Units (ADUs). We chose to tackle ADU policy first because, although it may not be the most impactful of potential tools, reform of Boulder’s ADU rules is on the city staff work plan for this fall, and because we feel many of the potential reforms are relatively simple code changes.

We have reached consensus on six simple changes that could be quick to implement, simple, and require no significant funding. We have also discussed longer-term, more challenging, or more costly changes, and we may be bringing some of those forward in the future. But for now, these are the quick-fix code and policy changes we recommend:

1. Eliminate saturation limits

Current rules limit the fraction of properties with ADUs within a given area. For instance, in the city’s largest residential zone district, RL-1, only 20% of properties within a 300′ radius are allowed to have ADUs.

This limitation was put in place originally to alleviate fears of an overabundance of ADUs. The limit was raised as part of the 2019 ADU code revisions, but it remains an obstacle to creating more ADUs in some areas of town, particularly since nonconforming properties such as duplexes are also included in the calculation. Perhaps as importantly, it is an opaque and confusing metric that may deter would-be ADU developers, and it slows the ADU permitting process. It’s impractical for a property owner to determine on their own whether their property meets the limits. Only city staff have the data and tools to do the calculation, and it must be done by hand (the city’s GIS software can’t do it automatically). Last and perhaps least, this provision significantly complicates the ADU code in the Boulder Revised Code.

2. No parking requirements for an ADU, or triggered by ADU construction

The ADU rules currently require one off-street parking space for a market-rate ADU. Moreover, they require that in order to build a market-rate ADU on a parcel that does not have the required one off-street space for the primary house, two parking spaces (one for the house and one for the ADU) must be provided.

These are significant impediments on constrained lots, or those with limited street access. They are also contrary to Boulder’s efforts to reduce incentives for motor vehicles and to create a less car-dependent urban form.

3. No lot-size minimum for ADUs

Current rules do not allow an ADU on any lot smaller than 5,000 sq ft in size. While such lots are fairly rare in Boulder, this restriction seems unnecessary and arbitrary.

4. Increase ADU size limits

The following table shows the current ADU size limits:

Attached1/3 dwelling size or 1000 sq ft, whichever is less½ dwelling size or 1000 sq ft, whichever is less
Detached550 sq ft800 sq ft

To encourage ADUs sized appropriately for families, we recommend increasing the size limits at least for detached ADUs, perhaps to 650 sq ft for market-rate, 900 sq ft for affordable. Alternatively or in addition, the size-limit exception process could be changed from one requiring a hearing at BOZA (Board of Zoning Adjustment) to a simpler administrative process.

5. Allow one attached and one detached, or two attached, ADUs per parcel

The existing rules do not explicitly limit a property to a single ADU, though that may be implied, and it was probably the legislative intent when the rules were passed. In any case, that has been the operating assumption. 

Based on suggestion from City Council, we recommend explicitly allowing one attached and one detached ADU, or two attached ADUs, per parcel. Many property owners are not able to or interested in providing an ADU. Allowing those who are able and interested to create a second ADU would help to meet our housing needs.

6. Allow ADU permitting before or at the same time as house permit

Yhe Planning Department only accepts an ADU application for parcels where a primary house alreadyexists or construction permits have already been issued. 

This results in an inefficient and costly process. First the property owner must submit an application for the house and receive a building permit—a 4 to 6 month process.  Only after the building permit issues will the Planning Department then receive an application for an ADU permits—taking another 4 to 6 months. So construction happens sequentially. Therefore crews for excavation, foundation, framing, etc. do their work for the house, and then must return — months later — to do similar work for the ADU. This is very inefficient.

It also means that an owner of any empty lot who wishes to build and perhaps live in an ADU first, before building the house, is not allowed to do so. This administrative restriction seems unnecessary and harmful.

These six are easy solutions to accomplish within the time period (6 months) set out by Council for drafting an ordinance to reform the permitting of ADUs. All six were part of the community discussion about ADUs in 2015-2018, so rather than tool up community engagement on these issues, we can use what was learned from the community during the last round, and go to public hearings before the Housing Advisory Board, Planning Board and City Council.

Representatives of Better Boulder, Boulder Is For People, and Boulder Housing Network worked on these ideas together. They are: Eric Budd, Jan Burton, Jake Brady, Ed Byrne, Chelsea Castellano, Macon Cowles, Rosie Fivian, Lisa Wade, Kathleen McCormick and Kurt Nordback.

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