Middle Housing Land Divisions

How do MHLD sewer services differ?

An MHLD is a type of land division that allows specified housing types to be divided into separate lots through an expedited process. MHLDs differ from standard land divisions in some key ways. To accommodate these differences, Environmental Services (BES) developed a sewer route-of-service policy unique to MHLDs.

In addition to standard, independent connections, the MHLD policy allows for two additional options for sanitary sewer connections:

1. Wye laterals
2. MHLD shared sewers

What is a wye lateral?

A wye lateral is when two individual building sewer laterals from the MHLD development join at a single wye fitting before connecting to the public sewer main.

MHLD wye laterals must meet Portland Permitting and Development (PP&D) requirements, including the following:

View full size image of The wye connection of a 6-inch sewer lateral. The configuration is in the shape of the letter "y".

• In the public right-of-way, the sewer lateral must have a minimum diameter of 6 inches.
• Installation: Wye laterals must be installed per the Double Sanitary Wye Lateral Connection (Figure 1) and follow city standard drawings and permitting requirements in P-262, P-257, and ENB- 4.17.
• Each branch of the wye can only serve one MHLD unit.
• A cleanout must be installed on each branch upstream of the wye fitting.

What is an MHLD shared sewer?

MHLD shared sewers consist of a single sanitary lateral connection to the public main, with the private sewer system on the property shared by the owners of the lots that the system serves.

MHLD shared sewers must meet Portland Permitting and Development (PP&D) requirements, including the following:

View full size image of Several buildings connected to a shared sewer lateral that crosses property lines in a section labeled private easement and maintenance agreement

• In the public right-of-way, the sewer lateral must have a minimum diameter of 6 inches.
• Installation: Follow the city standard drawings and permitting requirements in P-262 and ENB 4.17.
• The portion of the MHLD shared sewer system on private property must meet plumbing permit requirements and may require a plumbing code appeal.
• MHLD shared sewers require a private plumbing easement to be considered conforming sewers by BES under Title 17.32.
• Property owners are responsible for maintaining the shared system.
• All MHLD lots shall use the shared sewer unless technical constraints make it infeasible.

MHLD route-of-service options

Sanitary sewer route-of-service options acceptable for MHLD developments:

• Individual sewer laterals that connect to the public sewer independently within each lot's frontage and do not cross other lots.
• Individual sewer laterals that connect to the public sewer independently by crossing one or more lots within the MHLD parent parcel through associated private plumbing easements.
• Individual sewer laterals that wye together with no more than one other lateral from the same MHLD development.
• An MHLD shared sewer with one lateral connection to the public main through associated private plumbing easements.

Other considerations

• Depending on the location and availability of BES public sewer infrastructure, the developer may be required to extend the public sewer in the right-of-way under a Public Works Permit to enable an approvable route of service.
• One or more sewer laterals may be allowed to cross neighboring private properties outside the MHLD parent parcel in private plumbing easements, subject to BES administrative rules regarding the route of service—see determining route of service (section 6.A.3).
• Factors such as easement configuration, pipe material, and location of private plumbing lines may require a plumbing code appeal to meet plumbing permit requirements—see private plumbing easements.