Zoning overlays modify or override the base zoning regulations. They are sometimes part of the zoning code, and sometimes separate, but they alter what you are allowed to build on a property.
They are called different things by different cities (overlays, special districts, regulating plans, urban villages, plan districts, combining districts, neighborhood plans, etc.).
There can be dozens of them for each city, and they are important to discover, analyze, and incorporate into any feasibility study for a site.
Why do these zoning overlays exist?
Zoning overlays were added to the zoning code to make further adjustments, refinements, or incentives to specific areas in a jurisdiction.
As opposed to rewriting the entire zoning code, it was often easier to just add an exception to a specific area on top of the existing regulations.
Over time, these exceptions and overlays have built up, creating an astounding complexity.
The City of Los Angeles Planning Department explains it this way:
The current zoning code is the result of decades of amendments and supplemental layers of land use regulations that were added on top of the existing regulations to achieve specific goals that transcended what the prior zoning laws could accomplish. Approximately 66.24% of the lots in the City of Los Angeles have one or more overlays applied to them — a patchwork of regulations that are applied to specific properties across specific geographic areas.
That's a good summary: decades of amendments and supplemental layers creating a patchwork of regulations.
Do overlays exist in every city?
Generally, the larger the city, the more overlays there are. For the reasons above, large cities have spent a lot of time modifying and amending the zoning to account for nuances in specific areas, partly through the use of these overlays.
UrbanForm has currently aggregated 26 different overlays in Austin, TX. Plus, each of those overlays can have dozens of subdistricts (e.g., 65 sub-zones in the NPA overlay).
In total, 62.8% of the parcels in Austin are subject to at least one or more overlays that modify the zoning.
When we ran this analysis for Portland, Oregon, we found that 49.8% of the lots were subject to one or more overlays (though in reality, that figure is essentially 100% because of a particular overlay called Pattern Areas which cover the entire city).
In Seattle, it's 45.8%.
And as noted by the City of Los Angeles itself, that percentage is exactly 66.24%.
Do I need to worry about overlays?
In short, yes. Because if you think you can build to a certain height, or maximum buildable area because of the base zone designation, you're probably wrong.
And consequently, if you get zoning information that doesn't have a thorough analysis of the applicable overlays, you should be skeptical that it is complete.
How do I find the zoning overlays?
The disappointing answer is that it varies in every city. Every city has different regulations as well as different ways that the city communicates these regulations.
Sometimes the information is digitized; sometimes it is not. If the information is digitized, there are often many versions of it kept online in various states of maintenance and authority.
There are essentially 3 ways to get accurate, complete, and verifiable zoning information, which should include all of the applicable overlays:
1. Hire a local professional
This is usually an architect, land-use attorney, or contractor. They can work with you to explain nuances in the code, process, and even develop initial design schematics to help you visualize potentials.
These professionals cost money and take time. This process usually can take weeks and cost thousands of dollars, depending on the architect, and is usually the most comprehensive approach.
2. Do the research yourself
Start by searching the local government websites. You'll need to understand the authorities-having-jurisdiction (AHJs), and then you'll need to find the right maps and get the right text.
Next, you will need to draft the site to scale to be able to take the correct areas measurements and setbacks required for the formulas that often govern building regulations (such as FAR or coverage limits).
Then, you'll make an appointment to confirm your analysis with the city officials. Depending on your familiarity with the codes and the local bureau processes, this can also take days to weeks.
If this is the best option for you, UrbanForm has created guides to help individuals navigate the many bureaus, sources, and overwhelmingly large documents that need to be analyzed. We also try to explain the acronyms and jargon that are used throughout each jurisdiction.
We do this because even if people are not using UrbanForm, we believe increased access and proficiency with zoning will result in better buildings and cities. Find those guides to zoning here.
3. Use UrbanForm to get the results immediately
UrbanForm was designed to standardize and automate the entire process for you; gathering the most authoritative information from the correct sources and making it available online, instantly.
Because we understand the process of establishing the correct zoning is a long one involving many parties, we've taken care to document exactly where all of the source information comes from and provided links to those specific spots in the zoning code.
From our experience, if the information is not verifiable, it's not worth very much.
UrbanForm can help you verify everything in the code that applies to a particular property.
Depending on how much your time is worth, one or another of the above options might be the best fit for you.
UrbanForm is trusted by architects, so everyone else can, too
We're extremely proud that architects are the majority of UrbanForm's customers. We know how hard it is to provide meaningful zoning information because we've been in their shoes.
UrbanForm is trusted by architects to help them get the zoning right. Which means everybody else can trust it as well.