The new wastewater discharge permit issued to the Milwaukee Metropolitan Sewerage District (MMSD) is the first in the U.S. to mandate green infrastructure. The permit requires that green infrastructure not only be used to capture 3.8 million L (1 million gal) of stormwater by 2013, but an additional 3.8 million L of capacity must be added each year throughout the permit term. MMSD has an ongoing open spaces conservation program called Greenseams, which can be used to fulfill 75% of the 3.8 million L (1 million gal). However, 25% must come from municipalities and private property owners.