On the Hill: The Post Construction Rule

The EPA is currently developing a proposal that would impose requirements on new developments, redevelopments and MS4s (municipal storm-sewer systems) to reduce the quantity of stormwater runoff.

Washington, D.C.—The EPA is currently developing a proposal that would impose requirements on new developments, redevelopments and MS4s (municipal storm-sewer systems) to reduce the quantity of stormwater runoff. Stormwater quality is already regulated by the EPA through the Clean Water Act; regulating quantity would be something new, and could hold developers to some significant and expensive performance standards.

NAHB is calling this proposal “the post-construction rule,” since it doesn’t have an official name yet. Susan Asmus, senior vice president of NAHB Environment, Labor and Land Development, tells MHN that the EPA is talking about this rule requiring an 85 percent to 95 percent retention rate of all stormwater. “That’s pretty significant,” she says. “So if I’m going to put an apartment complex on a new piece of land, while I’m doing all the designing and engineering work, I also have to plan for retaining the vast majority or stormwater that comes off those structures on site.”

Developers putting in a new condominium community, for example, would have to install a stormwater holding facility. “In most cases, it’s bigger than what you’re putting in now,” Asmus says. “You will be very much encouraged to infiltrate water into the ground, which creates a whole slew of other problems associated with stability and engineering design.” The EPA wants to encourage redevelopment, so new development projects would be held to higher standards than redevelopment. Some big questions are still up in the air, however, especially as to long-term operation and maintenance and where exactly responsibility would lie.

There is also some question as to the EPA’s authority on this, as the Clean Water Act specifies regulation of quality, not quantity. Quantity has become an issue because the EPA believes that more stormwater runoff translates into more pollutants percolating into the ground as well as more potential for flooding. Because there is no federal requirement on quantity, it is usually addressed at the state or local level.

“The other piece of this rule is what they’re calling retrofit,” Asmus says. “They’re saying that municipalities have to develop a retrofit plan and implement it.” What is not clear—and this is where private developers should be highly concerned—is whether or not these retrofit plans would apply only to the municipal operations or to anything in the municipality. “So is the municipality going to say, anyone who owns an acre or more of impervious surfaces—buildings, parking lots, etc.—has to retrofit it to retain x percent of the stormwater on site? If you think about your local shopping center, which is all parking lots and buildings, this rule could require that shopping center owner to go dig up half the parking lot and install, essentially, a giant underground swimming pool to hold the stormwater that’s generated from that site. Doing something like that is horribly expensive.”

The six states in the Chesapeake Bay watershed have already been addressing retrofits to restore the Bay. These changes were also required by the EPA, although through different laws. In cases like these, stormwater utilities are being used to help spread the cost of stormwater management. “Houses are charged $10 a month. Commercial buildings, depending on the size, are charged $30 a month or so,” Asmus says. “The money goes to either a general fund or a dedicated fund for stormwater management, which will go toward doing retrofits, long-term operation and maintenance.”

The EPA expects to have a proposal out soon on this, with the hope that final regulation could be in place by November 2012. As soon as it’s finalized, Asmus says, “that will be a lawsuit waiting to happen. It will be a number of days before someone files suit on that one, and it will be industry.” The municipalities are already upset, because they don’t know how they are going to pay for the retrofits. Most of them don’t even know this proposal is in the works and “will be completely hit upside the head by this giant requirement.”

Separate from the post-construction rule, the EPA is also pushing to raise standards on stormwater quality. In December 2009 it came out with an effluent limitation guideline (ELG), which is a technology-based standard for new development during construction. Asmus says, “There is a lot of concern about stormwater during construction because the ground is beat up and disturbed and there is a lot more potential for stormwater coming in contact with pollutants and getting into rivers and streams.”

Although this kind of regulation already exists through the Clean Water Act, the ELG has two components that the EPA believes would do more. The first component is based on best management practices, and the second sets numeric limits on the level of pollutants in stormwater at construction sites. The EPA’s data has since been contested, which has sent the process back a few steps. The EPA expects to come out with new numbers in early 2012, which will then be up for public comment.