"We are going to do everything we can to make this happen," Dahme said. "Our goal is to have it in place on July 1."
The Unified Business Owners Association of Philadelphia, which says its members employ 16,000, has been pushing since fall for relief.
"This is a temporary patch for us," said Jeff B. Allen, cochair of the business group and president of Allen Bros. Wholesale Distributors.
"We appreciate what they've done," he said of the Water Department, but "we're still paying an exorbitant amount for storm water."
In July, the Water Department changed the way it collects money - roughly $112 million this fiscal year - for processing the rain that runs into the city's sewers from buildings and parking lots.
The old fees were based on the amount of water that a commercial property owner used. The new plan is based on parcel sizes, with an emphasis on the amount of impervious space. The change meant some property owners with large lots and little water use faced annual storm-water fees equal to or greater than their property taxes after a four-year phase-in.
Other property owners - big consumers of water with relatively small parcels, such as owners of Center City skyscrapers - are seeing steep declines in their monthly bills for storm water.
The billing shift was complementary to a broad effort by the city to comply with federal Clean Water Act regulations that are forcing municipalities to prevent the pollution of rivers and streams by runoff.
The proposed savings would be significant for some property owners. "It will save me in the first year about $110,000 and in the second year $220,000," said David Wolf, who owns 13 industrial buildings with 1.5 million square feet of space.
Even so, Wolf's annual bill for storm-water management already has climbed to $120,000 from $15,000 before the change, he said.
Wolf is one of two members of Unified Business Owners on a new Customer Advisory Committee, which will make recommendations to the department on how to handle storm-water fees in the future. The committee had its first meeting April 27.
The Water Department's Dahme said she expected, among other things, the group to recommend extending the phase-in period to give property owners more time adjust.
Contact staff writer Harold Brubaker at 215-854-4651 or email@example.com.