In Portland, all properties have a base residential, commercial or industrial zone. Some sites have additional restrictions overlaid on top of the base zones, aka ‘overlay’ zones. Specifically, these special overlay designations address particular conditions tailored to certain areas within Portland. They provide a layer of code protection for safety or sustainability reasons or to preserve the integrity of the area or site. These overlay zones include the Aircraft Landing Zone (h), the Environmental Zones (c or p), the Scenic Resource Zone (s), the Design Overlay Zone (d), and numerous others. The z-overlay is a ‘Constrained Sites Overlay Zone.’
Many homeowners in Portland benefit from the ability to have more than two dwelling units on their property. This land ownership perk resulted when the city approved the Residential Infill Project several years ago as a means for achieving denser development and increased housing options in residential zones. However, the z-overlay reduces the development potential of residential sites within this overlay in order to minimize personal and property risks related to natural hazards.
What criteria determine if a site is in a z-overlay?
Residential lots in the R20 through R2.5 zones carry a z-overlay designation if ANY portion of the lot has one or more of the following constraints:
- Environmental Conservation overlay zone (c),
- Environmental Protection overlay zone (p),
- Pleasant Valley Natural Resource overlay (v),
- Landslide hazards,
- Wildfire hazards,
- Flood hazards,
- Airport noise hazards, or
- Industrial sanctuary comprehensive plan designation.
How do I know if my property is in a z-overlay?
Official Portland zoning maps provide the information needed. Look for the letter ‘z’ as one of the map symbols.
First, visit PortlandMaps. Next, enter your address. Then, click on the word ‘zoning’ on the right-hand side. The map will show the base zones and any overlay zones. If your site has a ‘z’ on it, you are in a z-overlay. Even if just a portion of your site falls within this reference, this means your entire site is considered part of the z-overlay.
How does this code impact what I can do on my site?
The z-overlay reduces the number of dwelling units you can build on your site to a total of two – one primary unit and one accessory dwelling unit (ADU). Depending on the zone designation, some homeowners may normally be able to build 3, 4, 5, and even 6 units on a site. However, if you have a z-overlay, you are capped at two – one primary unit, and one ADU. PERIOD.
The Portland Bureau of Planning and Sustainability established these designations. AND, they are not adjustable.
PleaZe help
Do these zoning codes seem confusing or frustrating? We can guide you through the code chaos. For every project, CA performs a zoning analysis to advise property owners on what they can and can’t build on their sites. Let us help you make the most of your property or determine if a potential site supports your future goals. Give us a call.