EPA's Proposed Stormwater Regulations Could Significantly Impact Virginia Localities and Developers in the Chesapeake Bay Watershed

March 10, 2010

Just when localities with municipal separate storm sewer systems (MS4s) and developers thought they could breathe easier now that Virginia’s new stormwater regulations have been relaxed and suspended, the U.S. Environmental Protection Agency (EPA) announced that it intends to modify and strengthen its stormwater regulations.

EPA’s notice of its intended rulemaking (74 Fed. Reg. 68,617 (Dec. 28, 2009)) indicates that the new regulations will be more expansive and stringent than the stormwater regulations adopted (and later withdrawn) by Virginia’s Soil and Water Conservation Board (SWCB). The new federal regulations, which raise significant issues regarding the scope and extent of EPA’s authority to regulate stormwater, also could significantly affect the stormwater controls required to comply with the Chesapeake Bay Total Maximum Daily Loads (TMDLs) now under development.

Overview of the Proposed Rulemaking

EPA’s Federal Register notice points to a National Research Council (NRC) report issued in October 2008 as the principal basis for the proposed rulemaking. Citing the rapid conversion of land to urban and suburban areas and widespread adverse water quality impacts of expanding impervious land cover, EPA concludes that its existing stormwater regulations (some of which are almost 20 years old) are not sufficient to protect water quality. The notice suggests that EPA has accepted NRC’s recommendation that the agency needs to radically change its approach to stormwater regulation.

The Federal Register notice indicates that EPA is seeking to strengthen its stormwater regulations by:

  • enlarging federal control over municipal stormwater systems by expanding the areas classified as MS4s;
  • establishing, for the first time, specific federal requirements, including standards, for new development and redevelopment;
  • developing a single set of requirements for Phase I and Phase II MS4s;
  • requiring MS4s to retrofit existing development with improved stormwater control measures; and
  • imposing additional specific stormwater control measures, particularly where necessary to protect sensitive areas.

Further, EPA stated during one of its recent “Listening Sessions” on the proposed rulemaking that it is considering using the new regulations to impose additional requirements to further reduce the impacts of stormwater on the Chesapeake Bay. 


Although EPA regulates stormwater from construction sites of one acre or more, it does not directly regulate stormwater from development following construction. EPA’s regulations require MS4s to address stormwater from new development and redevelopment, but as EPA points out in its Federal Register notice, areas classified as MS4s presently cover only about two percent of the total U.S. land area. Further, EPA’s current regulations do not require MS4s to implement specific standards with respect to post-construction development, redevelopment, or existing development.

Virginia, on the other hand, does directly regulate stormwater from new development and redevelopment through the state’s general permit for construction activities that incorporates standards governing the quality and quantity of post-construction stormwater runoff. However, these standards are viewed by many (including EPA) as insufficient to protect water quality, particularly in the Chesapeake Bay watershed. Accordingly, in 2009, the SWCB proposed revised regulations that would have established more stringent stormwater standards for new development and redevelopment, as well as criteria governing the approval of local stormwater management programs.

The proposed standards were highly controversial, with many localities and developers asserting they did not adequately consider the high cost of employing infiltration techniques required to meet the standards as well as the impact of the new standards on development projects already planned or underway.

In response to comments on the proposed standards, the SWCB revised the standards in a number of respects, including expanding the number of offsite compliance options and adding a grandfather clause exempting many ongoing projects from compliance with the new standards. The standards themselves were also modified in response to new findings by the Chesapeake Bay Program which indicated that earlier nitrogen and phosphorus loading estimates called for larger reductions than needed to restore water quality in the Bay.

The revised regulations were adopted by the SWCB on Dec. 9, 2009, but were suspended Jan. 14, 2010, and republished for comment in response to citizen petitions. Legislation pending in the General Assembly indicates that the new regulations (in whatever form they are eventually adopted by the SWCB) will not take effect until late 2011, approximately one year before EPA plans to finalize its new stormwater regulations.

Potential Impact of the New Federal Regulations

The SWCB’s decision to relax the standards in response to the Chesapeake Bay Program’s increased nutrient loading estimates suggests that the standards will undergo significant revisions designed to reflect the Chesapeake Bay TMDLs now under development, and scheduled to be adopted by the end of this year. This, in turn, suggests that the new state standards may be more stringent than the current standards, because the TMDLs are expected to call for a net reduction in nutrient and sediment loads from stormwater and prevent new development from increasing stormwater loads in the future by imposing load caps.

However, given the controversy associated with the SWCB's proposal to lower the standard for new development from 0.45 (a calculated standard based on percent imperviousness) to 0.28 total phosphorus lbs/acre/yr, it must be assumed that the new state standards will not prevent new development from adding to the loads of nutrients and sediment discharged to the Chesapeake Bay watershed. Moreover, although the new regulations are expected to achieve nutrient and sediment reductions in stormwater from redevelopment, they are not expected to impose standards requiring retrofits to reduce nutrient and sediment loads in stormwater from existing development.

Consequently, while the new state standards will reduce the additional loads of nutrients and sediment in stormwater from new development and offset these additional loads to some extent with load reductions from redevelopment, the state standards cannot be expected to achieve the stormwater load reductions or load caps needed to comply with the anticipated wasteload allocations for stormwater in the Bay TMDLs.

EPA has clearly expressed its intention to do more than simply assume that states will achieve the load reductions needed to comply with the Bay TMDLs. The TMDLs must provide “reasonable assurance” that the load reductions required by the TMDLs will, in fact, be achieved, and EPA is calling on the Bay states to develop and submit Watershed Implementation Plans to fulfill this requirement. Further, EPA has threatened “consequences” for any state failing to submit acceptable Watershed Implementation Plans or failing to make steady progress toward achieving the wasteload allocations in the TMDLs.

Among the threatened consequences is the imposition of federal standards. However, as explained above, EPA presently has no direct authority over post-construction stormwater from development. EPA can be expected to use the federal stormwater rulemaking to try to establish the authority it believes it needs to impose federal stormwater standards, where EPA concludes that the state standards are insufficient to achieve the load reductions required to comply with the TMDLs.

Issues Presented by the New Federal Regulations

The proposed federal regulations pose a number of complex legal, policy and practical issues. Resolution of these issues will affect the scope and extent of the impact these regulations will have on localities and developers in the Chesapeake Bay watershed. More significant issues include:

  • Does EPA have the authority under the federal Clean Water Act to regulate stormwater from development? This issue involves not only the scope of EPA’s authority to regulate stormwater pursuant to Section 402(p) of the Act (33 U.S.C § 1342(p)), but also EPA’s authority to regulate discharges to manmade structures such as ditches, and its authority to regulate “potential” discharges in light of recent federal court decisions. EPA has expressed a strong preference for controlling stormwater by reducing the imperviousness associated with development, and this raises issues related to EPA’s authority to regulate land use, particularly land use associated with existing development that is not undergoing redevelopment.
  • How will the federal regulations be implemented in the Chesapeake Bay watershed?
    • Will they take effect even if Virginia submits Bay TMDL Watershed Implementation Plans that are accepted by EPA and the state continues to show acceptable progress toward achieving the stormwater load reductions required by the TMDLs?
    • There will be 92 Bay TMDLs – one for each tidal watershed segment (35 in Virginia). Will the regulations allow EPA to defer imposing the federal standards on stormwater sources in TMDL watersheds that are on target to meet their allocations even if stormwater sources in other TMDL watersheds are not?
    • Will the regulations allow EPA to defer imposing the federal standards on stormwater sources in TMDL watersheds that are not on target to meet their allocations due to sources other than stormwater?
  • Will EPA respond to questions regarding its authority to regulate land use by adopting standards as numeric stormwater discharge limits (as it did in effluent limitation guidelines recently adopted for construction sites), or will it adopt standards expressed as best management practices?
  • The new state standards were criticized for not giving adequate consideration to the hydrology and soil types present in Virginia. Will the federal regulations take into account differences in regional hydrology and soil types?
  • Will the regulations provide for local program delegation, and if so, will they allow Virginia to employ the delegation procedures in state law?
  • Will the regulations provide for offsite compliance options, and if so, will they allow Virginia to employ the options in state law?

In conclusion, while a great deal of attention rightfully will be focused over the next year on the continued development of the state's new stormwater regulations and the Chesapeake Bay TMDLs, an unpleasant surprise may await those who ignore the pending federal stormwater rulemaking.

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