Today, Austin faces a housing affordability crisis driven by rapid population growth and increasing economic disparity. With a significant housing shortage, particularly in affordable units, Austin must build both in existing neighborhoods and in new communities on the periphery to balance its housing market. This report evaluates a series of recent housing projects in Austin in search of a sustainable model for residential development that balances equity, ecology, and economy. This analysis finds that no existing model provides affordable housing with good access to transit and urban amenities that can be marketed and reproduced at the scale necessary to balance Austin’s housing market. This report then analyzes the formal qualities that make housing development efficient and affordable for developers, taxpayers, and residents. An analysis of density and building construction technology explores the convoluted relationship of density and per-unit land and construction costs. Then, a case study evaluates and compares a series of street grid designs drawn from cases as varied as Tokyo and outskirts of Austin. Each grid is evaluated based on indicators of efficiency and walkability. This report identifies that there is likely an optimal density for maximizing per-unit affordability, which varies by land cost. This report also finds that, disregarding net density, automobile scaled infrastructure grids with large blocks and wide rights-of-way are found to perform well for development efficiency, but poorly for walkability. Alternatively, pedestrian scaled infrastructure grids with small blocks were found to be equally efficient provided that they were designed with narrow rights-of-ways for local streets. While highlighting lessons particular to Austin, this paper provides insights on housing affordability issues shared by many other cities, adding to the discussion of how to most sustainably deliver affordable housing in America’s growing cities.