415 W. Washington St. is an approximately 2.75-acre city-owned site located on the south side of West Washington Street between First and Third Streets, just west of downtown Ann Arbor. The Ann Arbor YMCA is located to the north; the Old West Side Historic District borders the site to the south and west; and to the east, a heavy rail corridor, generally aligned with the proposed Treeline Trail, separates the property from downtown.

The city is considering a redevelopment concept for this site submitted by BaseBld. The proposal envisions approximately 100 multifamily dwelling units built in two phases. The first phase would include rental housing, while the second phase could be either additional rentals or condominiums depending on future housing conditions. Fifteen percent of the homes are proposed to be affordable to households earning 60% of the Area Median Income.

More broadly, the project is intended to reintroduce housing on a property with a complex history and known site constraints, while connecting it more intentionally to the surrounding neighborhood. The concept emphasizes sustainable building practices and a design approach intended to fit within the character of the area.

Currently, the land at 415 W. Washington St. will be used throughout 2026 as a staging area for a nearby sanitary sewer project.

To move forward, a purchase and sale agreement between the development team and the city would need to go before the City Council.

As part of the city’s due diligence, environmental testing was completed for the property. The results identified limited, historic groundwater contamination, which has been closely studied by the city and environmental regulators.

Follow-up testing confirmed that conditions in nearby buildings do not pose a public health concern. State and county agencies are continuing routine monitoring and, where appropriate, are overseeing standard mitigation measures to ensure public safety.

For a more detailed summary of these conditions, an environmental report was presented at the Ann Arbor Planning Commission meeting of Feb. 7, 2023.

The Michigan Department of Environment, Great Lakes and and Energy and the Washtenaw County Health Department have created two summary documents related to environmental concerns in the area:

• Vapor Intrusion Investigation near 415 W. Washington St.
• Argus I and II Buildings Environmental Investigation

The BaseBld proposal hopes to build off the community engagement and entitlement work that has already occurred.

In 2023, the City Council approved a Planned Unit Development (PUD) for this site after a public planning and engagement process. The full PUD approval can be found at this link.

BaseBld intends to advance their project within that previously adopted vision. The PUD plan describes certain features and constraints, including:

• Remediation of the contaminated brownfield site
• Building a segment of the Treeline Trail
• Providing affordable housing
• Preserving the chimney for chimney swift bird habitat
• Contributing to the character of the Old West Side Historic District
• Improving the floodplain from the existing condition

The site presents several physical and environmental challenges, including floodplain and floodway areas, legacy environmental contamination, and the need to construct public infrastructure such as the Treeline Trail. Addressing these conditions so the property can be safely and productively reused is expected to require some level of public participation, which may include the use of tax increment financing (TIF).