Sara C. Bronin is the founder of the National Zoning Atlas and the author of “Key to the City: How Zoning Shapes Our World.”
Zoning — the local power that governs what types of housing can be built and how — has, for too long, operated under the radar. Last year, a major report published by the Delaware Affordable Housing Production Task Force shed much-needed light on zoning’s negative impacts, especially on housing production and affordability. In part due to restrictive zoning rules, the fast-growing state isn’t building housing fast enough for its million-plus residents, especially the 20,000 lower-income households seeking affordable rental units.
This summer, the legislature took decisive action, passing the Housing for Every Delawarean Act to root out zoning laws that hinder housing construction. As someone who studies land use reforms nationwide, I believe the act has promise. But to really ensure that the new law fulfills its potential, legislators and the state agencies implementing it must start with a baseline understanding of how zoning works. And they must measure progress against that baseline, to ensure local-government accountability for regulatory changes that actually increase housing supply.
Fortunately, a newly created public resource — the Delaware Zoning Atlas — offers the first standardized information about the state’s local zoning rules. I lead a team of researchers who read 9,400 pages of Delaware zoning codes and pulled critical datapoints about housing-related rules from them. We also digitized the boundaries of over 500 distinct zoning districts, accounting for overlaps. Then, we put all this information on a public interactive map. Now, instead of reading thousands of pages of zoning codes, people can hop online to quickly understand how their county, city, town or neighborhood zones.
Our data paints a picture of a state that offers very little in terms of housing choice. Two images from the southern half of the state illustrate this conclusion. The first image shows that most residentially zoned land allows single-family housing by right. Statewide, 98% of residentially zoned land allows single-family housing. The second image shows that strikingly little land — just 12% of residentially zoned land statewide — allows apartments by right. Apartments are largely relegated to cities — like Dover, Newark and Wilmington — and to busy commercial corridors. But the need for such housing persists in every part of the state and every type of community.
In addition to documenting the number of units that can be built on each zoned parcel, the Delaware Zoning Atlas logs other rules that impact housing production and prices. It shows, for example, that 99% of single-family land requires a minimum lot size, higher than the national average of 90%. Minimum lot sizes increase land costs per home because, by definition, they limit the amount of housing that can be built. In addition, we found that 99% of residential land in Delaware comes with parking mandates. Studies have shown that these mandates increase housing prices and traffic, and most housing experts agree that it’s best to eliminate them altogether. Delaware has less land permitting accessory dwelling units by right (28% of single-family land) than the national average (34%). In other places, legalizing accessory dwellings has been seen to be an effective strategy for diversifying housing options, even in existing single-family neighborhoods.
These findings confirm the vital imperative for statewide action on zoning. The cumulative effect of Delaware’s 57 zoning codes is to make the most affordable types of housing the hardest to build. Without a range of housing options, teachers, nurses, retirees and young families are locked out of their neighborhoods of choice.
From a more practical standpoint, the Delaware Zoning Atlas can be useful to the dozens of localities required by the Housing for Every Delawarean Act to undertake zoning reforms to effectuate their affordable housing plans. Using the map and the Zoning Snapshots, local officials can calculate how much of their land allows particular types of housing, requires certain lot sizes or has a parking mandate or height cap. They can assess how their zoning compares with neighboring communities, spurring friendly competition — or even coordination — that advances reforms. As localities amend their codes, they can send updates our way, so we can post progress on the public map in real time.
In a few years, we can assess how many housing units the new law enabled. Did zoning laws change to allow more multifamily housing and accessory dwellings? Were lot sizes and parking mandates reduced or eliminated? Did zoning processes become simpler and clearer? Public access to clear answers about zoning reform can ensure that zoning moves from under the radar to into the light.
Reader reactions, pro or con, are welcomed at civiltalk@iniusa.org.
