Do Stormwater Basins Generate co-Benefits? Evidence from Baltimore County, Maryland

- Stormwater infrastructure has potential for co-benefits that increase house prices.
- We use a difference-in-difference hedonic model to examine this proposition.
- Co-benefits promise does not hold; house prices are lower from basin proximity.
- Policy responses to stormwater regulations can create disamenities for households.

An often-cited advantage of green infrastructure projects is the potential for “co-benefits” generated from its natural features, which depend on the generation of positive house price capitalization. Using housing transactions data and exploiting variation in placement and design, we examine the capitalization of stormwater retention basins, a common green infrastructure project in suburban housing developments. Results show adjacency causes decreases in housing prices between 13 and 14% for the average home. Additionally this negative effect exacerbates with basin age. Rather than providing co-benefits, we find that stormwater basins generate a cost for proximate households.