Maine’s population is aging – by 2030 over 25% of the state will be age 65 and older and the demand for affordable housing is going to increase at a time when total development costs (TDC) are rising and profit margins are shrinking. By developing low-income housing units now, Maine can adequately house its senior population and provide affordable housing for its younger generations. This research began with the goal being to identify the variables that drive up development cost. Specifically, what costs are rising, when they’re rising, and what’s causing them to rise. Ultimately we want to provide metrics and analysis to guide future decision-making in the affordable housing market. While the purpose of this paper is to correlate varying types of projects to development cost trends, the relatively small number of projects with adequate cost data limited the conclusiveness of any findings. Still, these findings may prove helpful and meaningful in the selection process of future affordable housing developments. Total Development Cost (per unit) has actually been on a downward trend for most project types the past 10 years, with a more pronounced declining trend from 2012 onward. The exception is Acquisition Rehab projects and projects receiving the 4% Tax Credit, which saw slight increases in their per unit cost trends. Construction costs are on the rise, which is concerning since they constitute so much of the budget. This is being combatted by lowering costs elsewhere and increasing the amount of units per project, thus achieving greater cost efficiency through economies of scale. There are many moving variables determining development costs, but the most consistently influential were the construction type of the project, the tax credit it receives, and the type of people it plans to house.