Middle Housing Land Divisions

Learn more about how to obtain a Middle Housing Land Division.
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What is a Middle Housing Land Division (MHLD)?

An MHLD is a type of land division that allows specified housing types to be divided into separate lots through an expedited process. A limited set of approval standards apply to an MHLD application. Most approval criteria that apply to a standard land division do not apply to an MHLD application.

There are several primary distinctions between an MHLD and a standard land division. For an MHLD:

  1. No more than one dwelling unit is allowed per lot, regardless of the zone. No ADUs are allowed.
  2. MHLDs are only allowed with duplex, triplex, fourplex, and cottage cluster housing types.
  3. MHLD lots cannot be further divided.
  4. New parcels or lots do not need to meet street frontage requirements or minimum lot size standards.
  5. The residential structure type developed on the middle housing land division site remains the same structure type after the land division is complete for the purposes of Zoning Code standards (e.g. a triplex remains a triplex).
  6. Zoning code development standards continue to apply to the original site even after the land division is complete.

Middle Housing Land Division Process

Like standard land divisions, Middle Housing Land Divisions (MHLD) are a two-step process that includes:

  1. Preliminary Plan review and approval: MHLD applications are processed as an Expedited Land Division.  
  2. Final Plat review and approval: Following approval of the MHLD preliminary plan, a final plat application must be submitted for review. Once the final plat is approved and recorded, the land division process is complete.

The MHLD process is unique in a number of ways. Please review the list below to help you prepare.

  • MHLDs are allowed in conjunction with specified housing types and will only be approved if a qualifying development, such as a triplex, is proposed, approved or existing on the site.
  • For sites that don’t have existing or approved development, building permits must be under review prior to submittal of an application for an MHLD. To ensure reviewers identify potential issues during permit review, applicants must declare an intent to divide at the time of building permit application.
  • MHLD applications use the Expedited Land Division process set by state law. The City must either approve or deny the application within 63 days of it being deemed complete. No extensions are allowed and there will be very little time to submit new information. Therefore it is very important to make sure all issues identified in the completeness review are resolved before requesting the application be deemed complete.
  • Because the building permit will be issued before the land division final plat is complete, any right-of-way dedications or public works requirements, such as performance guarantees or easements granted to the City must be completed prior to building permit approval.
  • Residential construction must be underway with an as-built survey of buildings and underground services provided before the final plat is approved.

Although not required, an early assistance appointment is recommended to identify service requirements, particularly public works permits, and important project milestones prior to submittal.

The document below provides a step-by-step guide on how to successfully complete an MHLD.

What housing types are allowed for a Middle Housing Land Division?

Middle Housing Land Divisions (MHLD) apply to residential development types only. The residential housing types, as defined in the zoning code, that are eligible for an MHLD are limited to those described below. For the purposes of applying zoning regulations, the housing type remains the same after the MHLD is complete.

This image illustrates the potential division of fourplex housing into four separate lots.
Here is a potential Middle Housing Land Division (MHLD) project of dividing a fourplex into four lots.
  1. Duplex. A duplex is defined as a building that contains two primary dwelling units on one lot. For a land division to be possible, the units must share a common wall (not floor/ceiling). 
  1. Detached Duplex. In the single-dwelling zones, a duplex can be two detached primary dwelling units on one lot. This allows a second primary unit to be added to a site with an existing house when it meets the following qualifications:
  • The existing house must be at least five years old.
  • The new unit may not be taller than 25 feet.
  • The lot must not be in an area with the Constrained Sites ‘z’ overlay zone.
  1. Triplex or Fourplex. A triplex or fourplex is defined as a structure that contains three or four primary dwelling units on one lot. For a land division to be possible, each unit must share a common wall with at least one other unit (not floor/ceiling).
  1. Cottage Cluster. A cottage cluster is defined as a group of three to 16 detached dwelling units on one lot per acre with a footprint of less than 900 square feet each that includes a common courtyard.

    Cottage clusters are groups of relatively small homes oriented around a shared common space such as a courtyard or garden. Not allowed: The common outdoor spaces may not include projections from individual units, such as eaves, bay windows, and patios.

    Cottage clusters are allowed in the RM1, R2.5, R5 on sites at least 5,000 square feet in area and in the R7 and R10 zones on sites at least 7,000 square feet in area. There is a maximum site is of one acre. See Portland City Code Sections 33.110.265.G and 33.120.270.G.

Projects that do not qualify for a Middle Housing Land Division

Below are examples of situations that do not qualify for a Middle Housing Land Division. This is not an exhaustive list and does not capture all the scenarios that are not allowed:

  1. Vacant lots for future development
  2. Dividing buildings constructed to the commercial building code or non-residential development
  3. Development with more than one unit on each lot, such as a house and Accessory Dwelling Unit (ADU) 
  4. Detached houses, except for projects meeting detached duplex or cottage cluster requirements

Building Permit Submittal

Development on an MHLD site must meet the residential building code based on the proposed lot lines. It is important to apply for the correct permit type and design the building to appropriate building code standards. The table below provides a cross-walk between zoning code housing types, building code and City of Portland building permit types.

MHLD housing types, building code and permit type
Zoning Code Middle Housing TypeHow DividedBuilding Code (Oregon Residential Specialty Code)Building Permit Type
(2 attached units on parent site)
One unit per lot divided on common wallTownhouse
New Single Family Residential
  • One residential permit per unit
Triplex or Fourplex
(3 or 4 attached units on parent site)
One unit per lot divided on common wallTownhouse
Residential Batch
  • One RS permit per unit
  • Site Development permit
Detached Duplex
(two detached units on parent site - one unit must be existing house, 33.110.265.D.2)
One unit per lot meeting minimum building code separation from proposed lot linesOne-Family Dwelling
New Single Family Residential
  • One RS permit for new unit
Cottage Cluster
(3 to 16 detached units on parent site, 33.110.265.G and 33.120.270.G)
One unit per lot meeting minimum building code separation from proposed lot linesOne-Family Dwelling
Residential Batch
  • One RS permit per unit
  • Site Development permit

When submitting your permit application, it is crucial to identify your project as an MHLD. MHLD identification will help ensure reviewers understand your intent to divide the land and help raise potential issues early in the review process.

How to identify your MHLD project when submitting your permit application:

  • Development Hub PDX portal: Answer “Yes” when asked whether the permit will be followed by an application for a Middle Housing Land Division.
  • Residential permit submittal forms: Answer “Yes” to questions about whether a Middle Housing Land Division is proposed.

Additional building permit submittal requirements apply for Middle Housing Land Division projects:

  • The permit site plan must show the proposed lot lines and any proposed easements and tracts. Please provide dimensions from the proposed lot lines to the exterior walls and all projections (e.g. eave overhangs, bay windows, etc.).
  • Detailed utility plan for sanitary sewer, stormwater management, water service and franchise utilities (power, cable, gas, etc.), including connections in the right-of-way and on-site plumbing outside of buildings.

Application forms and submittal standards

Submittal Checklist

MHLD applications must include a proposal for eligible housing types specified in the Zoning Code (duplex, triplex, fourplex or cottage cluster). The application must include sufficient information to demonstrate that applicable zoning code, building code and service requirements are met. The following list includes the submittal requirements for both the building permit and MHLD applications. It is intended as a guide to address requirements for common situations but may not fully address requirements for all proposals.

Middle Housing Building Permit

The submittal of a building permit application must precede the MHLD application submittal. Buildings must be designed to the Oregon Residential Specialty Code (ORSC). Attached units must be designed to Townhouse standards.

Middle Housing Land Division Application

This should be submitted after the first building permit review has taken place (all reviewers have approved or issued a checksheet). See Portland City Code 33.671.030 for additional details.

  • Land Use Review application form: 
  • Written Statement that includes the following:
    • A complete description of the proposal including site layout and circulation, natural features, existing and proposed development and uses, and changes to the site or existing buildings
    • A description of how all approval standards are met
    • Additional information needed to understand the proposal
    • Names and addresses of land division designer or engineer and surveyor
  • Proof that building permit plans are under City review (unless existing development will remain and be divided)
  • Vicinity Map, extending at least 200 feet in each direction from the land division site, showing existing conditions for both the site and the vicinity including streets, pedestrian and bicycle facilities and connections, and the location of utilities and services
  • Plans illustrating the proposed land division in electronic PDF format. All plans must be drawn to scale and include a north arrow. The required information listed below may be grouped on several maps. The location of items not required to be surveyed must be accurately shown on the maps.
    • Surveyed information: 
      • Boundary lines of the site with dimensions and total site area
      • Proposed lot layout with sizes, dimensions, and lot numbers
      • Proposed tract layout with sizes, dimensions, purpose, and name
      • Proposed layout and widths of all rights-of-way including dimensioning and roadway width and proposed name of any new streets
      • Dimensions of proposed right-of-way dedications, including dedication to existing rights-of-way
      • Proposed location, dimensions, and purpose of all easements
      • North arrow and scale of map
      • Identification as the Preliminary Plan Map
      • Stamp of surveyor
      • If more than 3 lots are proposed, the proposed name of the land division
      • Existing development, including dimensions and distances to property lines. Structures and facilities to remain must be identified
      • Location and dimensions of existing driveways, curb cuts, and sidewalks on and abutting the site
    • Location, dimensions, and purpose of existing and proposed easements on and abutting the site
    • Site plan with proposed development and existing development to remain matching the building permit submittal
    • Existing and proposed services and utilities for each dwelling unit matching the building permit submittal and public works permit concept approval, if applicable
    • Any other information necessary to show that the approval standards are met

Note: Middle Housing Land Divisions are a two-step process. A separate application for Final Plat Review must be submitted after the Preliminary Plan is approved. The final plat survey must also be reviewed by the County Surveyor. The individual lots will be created when the approved MHLD final plat is recorded. 

MHLD Service and Easement Requirements

Applications for middle housing land division (MHLD) must demonstrate that adequate water, sewer, and stormwater facilities are, or will be, available to serve the proposed development. Separate facilities are required for each lot, including:

The preliminary plan for the MHLD must include easements or tracts necessary to locate, access, maintain and replace services to each dwelling unit. Easements for other utilities, such as gas, power and cable, should also be shown to ensure adequate space is available.

See Approval Standards in Portland City Code Section 33.671.130.

MHLD Service Requirements

The MHLD layout must provide sufficient street frontage to accommodate the spacing requirements for services to each lot, either directly or via an easement. It may be difficult to meet spacing requirements on sites with narrow street frontages or narrow easements. Spacing requirements in the public right-of-way and on the site may vary, and both must be factored into the lot layout for the MHLD.

Spacing in public right-of-way. General separation requirements in the right-of-way are described in the table below, but site-specific circumstances may require greater distances.

Horizontal Spacing Requirements in the Right-of-Way
Type of SpacingWater Service (3)Sanitary Sewer and Storm Sewer Laterals (1) (2)
Spacing between connections to public main18 in. between service line taps on water main

36 in. total for header service box (up to 6 meters)
3 ft. minimum skin-to-skin between taps

Only one tap is permitted per pipe section for concrete or clay sewer pipes (2)
Spacing between service types5 ft. from sewer5 ft. skin-to-skin from water line and meter
Spacing between other utilities (gas, power, cable)3 ft. from underground utility lines (2 in service and smaller)3 ft. skin-to-skin from gas line

(1) Refer to Chapter 5 of the Sewer and Drainage Facilities Design Manual.
(2) Storm sewer laterals should only be proposed when on-site infiltration of stormwater is not feasible, per Stormwater Management Manual (SWMM) requirements, and where an acceptable off-site disposal point (e.g. storm-only or combination sewer main) is available.
(3) Refer to Water Bureau Engineering and Technical Standards Administrative Rule.

On-site plumbing. On constrained sites, it is essential to plan ahead and map out all underground services and utilities to ensure adequate space is allocated for water, sewer, stormwater and other utilities. It is recommended that applicants contact providers for gas, power and cable early and include those utilities on their building permit and land division plans.

Generally, private service lines may be closer together on private property than in the public right-of-way. Spacing of services and utilities on private property can vary significantly depending on materials used. For example, up to 12 inches of both horizontal and vertical separation may be required between types of service or utility lines, while other materials may require no separation. To provide maximum flexibility in your layout, it is recommended that only plumbing materials approved for use inside a building be used on constrained sites. This choice of materials will allow for no separation. See the Oregon Plumbing Specialty Code (OPSC) for specific guidance.

Sanitary Laterals. Allowed sewer lateral configurations for MHLDs depend on the number of lots proposed and other site-specific constraints. Please see the MHLD sewer webpage for a complete description of allowed routes of sewer service for MHLDs.

Stormwater Management. Stormwater management facilities must meet the requirements of the Stormwater Management Manual (SWMM) and Oregon Plumbing Specialty Code. Most infiltration facilities must be set back a minimum of 10 feet from buildings and 5 feet from property lines abutting other sites. No setbacks are required for property lines abutting a right-of-way, though the facility must be located entirely on private property. Refer to Section 2.2.4 of the SWMM for facility-specific setbacks. Drywells may be shared by more than one lot if they are located in an easement and meet the requirements of the BDS Code Guide on Shared Drywells. Any other shared stormwater facilities would require a plumbing code appeal

Private easements. If water or sewer service lines cross another lot (e.g. for landlocked lots) or for any shared facilities, a private easement is required. Proposed easements must be shown on building permit plans and the preliminary plan for the MHLD. The recording of the final plat survey for the MHLD will create the private easements. A maintenance agreement, explaining how the easement area and facilities within the easement will be maintained, must be submitted for review by the Bureau of Development Services (BDS) with the final plat application and recorded with the final plat.

General requirements for private easements:

  • Sewer easements must be 10 feet wide, unless the requirements of the BDS Code Guide on Private Sewer Easements for a reduced width are met. 
  • Water easements must be 10 feet wide.
  • There is no limit on the number of individual service lines within the easement provided separation requirements are met.
  • Easements for shared drywells must be at least 10 feet by 10 feet and provide access for all of the lots served by the drywell.
  • Requests for reduced easement widths must be approved through a plumbing code appeal.
  • No structures or trees may be located within easements for sewer, water or drywells. Other landscaping and hardscape improvements, such as driveways, walkways and patios, are allowed.

Services may also be located in a tract separate from the lots. This could be a private street tract or common access and utility tract. Such tracts are generally commonly owned and maintained by all of the lots served by the tract, which is described in a maintenance agreement and recorded with the MHLD final plat. Tract size will vary depending on the proposed improvements located within the tract.

Public Mains Extensions.If a MHLD site does not have adequate sanitary, storm or water service, a public main extension may be required to serve the site. In order to ensure the separate Public Works Permit (PWP) process does not impact the ability to approve the land division, PWP Concept approval must be obtained and building permit plans updated accordingly, prior to the middle housing land division being deemed complete. The state-mandated MHLD timeline does not allow for extensions. Therefore, failure to obtain the required PWP approvals to demonstrate the feasibility of providing services during the required timeline could result in the MHLD being denied.

Public Utility Easements. Other utility providers, such as gas, power and cable, may require a Public Utility Easement in order to access lots that don’t have direct frontage on a street. It is recommended that applicants contact their service providers early and include any necessary easements on their building permit and land division plans. Public utility easements are commonly required to be 8 feet wide to accommodate multiple services.

Other Easement Requirements

In addition to easements related to City services and other utilities, the following easements may be required:

  • Access easement to provide access for lots without street frontage. The easement must allow pedestrian access to a street but may also allow vehicle access if other requirements for driveways and parking are met. This easement will need to provide for access by residents, emergency service providers, deliveries and visitors to the site. Access could also be accomplished through a private street or access tract.
  • For attached units, a private easement for maintenance of common building elements, such as fire walls, foundations, eaves, and rain drains.
  • Private easements for use and access to shared common areas such as outdoor area, trash and recycling, or parking. Common areas may also be placed in tract.

Proposed easements and tracts must be shown on building permit plans and the preliminary plan for the MHLD. The recording of the final plat survey for the MHLD will create the private easements and tracts. A maintenance agreement, explaining how the easement or tract area and facilities within the easement or tract will be maintained, must be submitted for review by the Bureau of Development Services with the final plat application and recorded with the final plat.