Decent, Affordable, Safe Housing for all Act or the DASH Act This bill provides grants, loans, tax credits, and other assistance to promote the building, maintenance, and affordability of housing. Specifically, the bill requires the Department of Housing and Urban Development to (1) provide housing vouchers to individuals and families experiencing or at risk of experiencing homelessness, (2) provide grants for the modular construction of affordable housing, (3) propose a new formula for distribution of Housing Trust Fund amounts, and (4) encourage zoning and community planning methods that promote multi-family housing. The bill also makes permanent certain homeless assistance programs. The Department of Agriculture (USDA) must provide additional grants and loans to construct or preserve affordable housing for farm laborers and may provide rural housing vouchers for low-income households residing in certain properties financed with a loan made or insured by USDA. The bill also provides statutory authority for a program to preserve and revitalize USDA-backed housing projects, including by restructuring existing housing loans. The bill expands the Low-Income Housing Tax Credit (LIHTC), including by increasing the credit for projects serving extremely low-income households. Further, the bill creates a refundable tax credit for participating owners of rental buildings who lower rents for their low-income tenants. The bill also creates a tax credit similar to the LIHTC for the development of housing for middle-income households and provides a tax credit of up to $15,000 for first-time homebuyers.