The Martha’s Vineyard Commission has approved a plan to expand the Sepiessa Affordable Housing development in West Tisbury.

The application from the Dukes County Regional Housing Authority and the Island Housing Trust will add three affordable housing units with six bedrooms to the housing development on Clam Point Road. Right now, the housing complex consists of four units with six bedrooms.

The development is located on a three-acre parcel of land with a Title V septic system.

The commission approved the project application as a development of regional impact with conditions on Nov. 1, with the decision noting that the development would have a positive impact on the supply of low and moderate income housing for Island residents, and a minimal impact on the environment and other persons and property.

The commission imposed conditions including replacement of the Title V system with a denitrifying and drip irrigation system, keeping fertilized turf to a minimum, submitting a landscaping plan to the land use planning committee, and limiting exterior lights on the buildings to what is required by code.