TL;DR (generated, confidence: high)

Portland's 15% street-facing window rule applies to new single-family residences and street-facing alterations on houses and residential structures, with specific exceptions for flag lots, steeply sloped terrain, and certain subdivisions. Windows must allow views to the street, and both garage wall windows and main entry doors count toward compliance.

Key points:

15% rule applies to new single-family residences (NSFR) and alterations/additions involving street-facing sides (How to calculate street-facing windows for your home ↗)
Rule does not apply to flag lots, lots with 20% or greater average slope from street, or subdivisions/PUDs with preliminary approval between 09/09/1990 and 09/09/1995 (How to calculate street-facing windows for your home ↗)
Qualifying windows must provide views from building to street, including windows in garage walls and main entrance doors facing the street (How to calculate street-facing windows for your home ↗)
On corner lots or lots abutting multiple streets, standard must be met on all street-facing facades (How to calculate street-facing windows for your home ↗)
Glass block windows, garage door windows, and vents do not count toward meeting the standard (How to calculate street-facing windows for your home ↗)
For alterations or additions, standards may be applied only to the portion being altered or added (How to calculate street-facing windows for your home ↗)

Entities: standard: 15% rule | requirement: street-facing facade | property_type: single-family residence (NSFR) | exception: flag lot | exception_context: PUD

How to calculate street-facing windows for your home

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Source: How to calculate street-facing windows for your home ↗ Last modified: Sun, 19 Apr 2026 20:06:03 GMT

When does the 15% rule apply?

This rule applies to houses, attached houses, and most structures that contain residential uses.

Project descriptions that apply:

Building a new single-family residence (NSFR)
Alterations or additions that involve the street-facing sides of your home

When the rule does not apply

Development on flag lots
Development on lots that slope up or down from the street with an average slope of 20% or more. For how to measure the average slope see 33.930.060 ↗.
Subdivisions or PUDs that received preliminary approval between 09/09/1990 and 09/09/1995

What counts toward meeting this rule?

Windows used to meet this standard must allow views from the building to the street.
Windows in garage walls do count toward meeting this standard.
A main entrance door facing a street lot line.
On corner lots or lots abutting more than one street, the standard must be met on all street-facing façades (the face of the building).
For an alteration or addition to an existing development, you may choose to apply the standards of this section only to the portion being altered or added.

What does not count toward meeting this rule?

Glass block windows and vents
Windows on garage doors