Housing Code Amendments

Snippets of duplex, adu and triplex in Olympia

What's happening?

The City plans for where and how Olympia will grow and what is needed to serve that growth (parks, open spaces, infrastructure, streets, public services, etc.) under the Washington State Growth Management Act (GMA). The GMA was amended in 2019 and again in 2020 to encourage cities to take steps to increase residential building capacity in urban growth areas. The updated GMA (RCW 36.70A.600) provides a list of options to do so.

After reviewing the options, the City Council identified three options that appear to be appropriate for the Olympia. The Council directed the Planning Commission to draft an ordinance to implement two or three of the identified options. Learn more about each below.

The Public Hearing for the proposed Housing Options Code Amendments took place September 23, 2020. The Planning Commission issued its recommendation letter at their Nov. 2 meeting.

The Planning Commission recommendation will be considered by the Council’s Land Use and Environment Committee at its meeting on November 19, 2020.  It is anticipated the full Council will consider these amendments at its meeting on December 8, 2020.

Proposed housing options code amendments

Public comments

Public comments about the proposed code amendments were accepted from January until Sept. 30, 2020.

Stay Informed


The City has issued a SEPA Determination of Non-Significance for the proposed code amendments.

duplex on a corner lot in Olympia

Duplexes on corner lots

Proposal: Allow duplexes on each corner lot in all zoning districts that permit single family residences.

For Olympia, that would mean a duplex would be allowed on almost all corner lots since almost all zoning districts include single family residences as a permitted use. In order to obtain a building permit the applicant would need to demonstrate compliance with setbacks from property lines, maximum building height and number of stories, maximum lot coverages, low impact development stormwater standards, parking requirements, and design review.

In order to comply with the “on each corner lot” provision of the statute, the minimum lot size would be the same size as the minimum lot size for a single-family residence of the underlying zoning district.

ADU in olympia

Accessory Dwelling Units (ADUs)

Proposal: Allow ADUs in association with a single-family residence (SFR), with a few specific provisions.

The specific provisions include:

  • Allow attached ADUs on all parcels with a SFR where the lot is at least 3,200 square feet in size
  • Allow both attached and detached ADUs on all parcels with a SFR, provided the lot is at least 4,356 square feet in size
  • No additional on-site parking required
  • No owner-occupancy requirement
  • Cannot limit the size below one thousand square feet
  • Must not prohibit the separate rental or sale of ADU and primary residence
  • Impact fees may not be more than the projected impact of the ADU
  • City may set other regulations, conditions, procedures, and limitations and must follow all applicable state and federal laws and local ordinances

In Olympia, ADUs are allowed on all lots with a detached single-family home, regardless of the lot size. This may need to be amended to address situations where an attached SFR is located on lots that are at least 3,200 square feet in size. Other amendments that would be needed include:

  • Eliminate requirement for an additional on-site parking requirement
  • Eliminate requirement for the property owner to live on site
  • Modify the size provisions so an ADU can be up to 1,000 square feet

The ADU option includes language that allows cities making use of these ADU provisions to also consider other local provisions. Optional issues the City may want to address include:

  • Maximum building height
  • Attaching an ADU to an accessory structure (e.g. detached garage)

Triplex in Olympia

Duplexes, triplexes and courtyard apartments

Proposal: Allow a duplex, triplex, or courtyard apartment on each parcel in one or more zoning districts that permit single-family residences unless a city documents a specific infrastructure of physical constraint that would make this requirement unfeasible for a particular parcel.

In order to implement this option, Olympia would need to determine which of these housing types would be appropriate in which zoning districts. Again, because of the phrase “on each parcel”, that would mean the proposed development would be allowed as long as the underlying development standards are met, such as setbacks from property lines, maximum building height and number of stories, maximum lot coverages, low impact development stormwater standards, parking requirements, and design review.

Because the statutory language includes the word “or” it seems each city could address these housing types separately. Just as an example, the final decision may be that duplexes are appropriate in the R 4-8 zoning district, whereas triplexes and/or courtyard apartments are not. Or another example might be that duplexes are appropriate in all zoning districts that permit SFRs, triplexes are appropriate in most residential zones, and courtyard apartments are appropriate in a few residential zones.


Contact Joyce Phillips, Senior Planner, at 360.570.3722 or housingoptions@ci.olympia.wa.us