Stormwater Management Practices - Rainwater Harvesting Is Cheapest By Far

Just finished listening to a presentation of the approved stormwater management techniques approved by the City of Atlanta. Atlanta is requiring that any new construction or remodeling include measures to reduce flooding in the city's creeks and combined sewers.

The costs, according to the presenter:

Green Roof: $20/square foot
Permeable pavement: $14/sf
Bioswale: $7-10/sf*
Rainwater Harvesting:$1/sf

*That's per square foot of permiable space, not per square foot of bioswale.

The rainwater harvesting cost is just the costs associated with reducing the stormwater outflow volume, not using the water. When allocating cost savings, it's best to compare rainwater tank costs with those of other stormwater management practices. Then compare the cost of water treatment and additional piping with the cost of purchasing municipal water for irrigation or other use.

Rainwater harvesting is the least expensive stormwater management technique. And then, it earns a substantial ROI if there is any use for the water.