Federal and State Stormwater Rules:
proposed rules could be costly for municipalities

(from Maine Townsman, June 1998)
by Linda Lockhart

When a papermaking facility discharges wastewater into the river, that is potentially a "point source" of pollution. Point sources have been relatively easy to identify and consequently have been the first targets of environmental protection efforts. A "non-point source" is much more difficult to identify and treat. Non-point sources include stormwater runoff from construction sites, or the flow of phosphorus carried from lawns into the lakes, or even dirt carried into receiving waters as the result of soil erosion.

Stormwater rules attempt to deal with some of the sources of "non-point" pollution. Currently, activities in Maine are only subject to federal stormwater rules for construction sites that are greater than five acres, large municipal storm sewers, and for industrial activities. However, proposed changes in the federal stormwater rules may have a greater impact on Maine. At the state level, Maine has adopted stormwater rules issued and enforced by its own Department of Environmental Protection (DEP).

Maine DEP’s current regulation of construction site stormwater runoff

DEP and the Board of Environmental Protection have adopted new stormwater management rules, Chapters 500 and 502, effective December 31, 1997. The two key factors of stormwater addressed by the rule are quantity and quality.

Scope of DEP’s rules, Quantity and Quality

Projects subject to DEP’s stormwater quantity standards include:

• Construction projects in the direct watershed of a "water body most at risk" that result in more than 20,000 square feet of impervious area, or construction projects that disturb more than 5 acres;

• Construction projects in any other area that result in more than one acre of impervious area, or construction projects that disturb more than 5 acres; and

• Projects that are defined as "development" under the site location of development law (38 M.R.S.A. 482).

Projects subject to DEP’s stormwater quality standards include:

• Construction projects in the direct watershed of a "water body most at risk" that establish more than 20,000 square feet of impervious area or disturb more than 5 acres;

• Construction projects in "sensitive or threatened regions or watersheds" that result in more than one acre of impervious area or disturb more than 5 acres;

• Projects that constitute a "development" under the Site Law; and

• Projects that involve infiltration into the wellhead protection area of a public water supply.

Projects that are exempt from the stormwater standards include:

• Forest management and farming activities;

• Projects covered by municipal ordinance that meets or exceeds the provisions of the stormwater law and is enforced;

• Construction projects at industrial facilities regulated under a federal stormwater or discharge permit;

• Construction of single-family, detached residence on a lot;

• Waste facilities regulated by DEP; and

• Maine Department of Transportation (MDOT) or Turnpike Authority projects subject to a memorandum of agreement between DEP and the agency.

DEP’s Standards

DEP’s stormwater rules have these measurable standards:

Quantity: Whether the peak flow after completion of the project exceeds the peak flow before the project began.


1. Phosphorus standard, whether, after application ofstormwater best management practices (BMP’s), phosphorous from project runoff exceeds the allowable per-acre phosphorous allocation for lakes;

2. Total solids standard, whether after application of stormwater BMP’s, the necessary percentage of total suspended solids are removed from project runoff; and

3. Basic stabilization measures standard, whether the design, construction and maintenance of site alterations, such as ditches and gravel roads, are in accordance with erosion and sedimentation control practices.

For specified small projects, a "permit-by-rule" process is available if certain design requirements are met, such as draining stormwater discharge into landscape buffers.

The Federal Environmental Protection Agency’s (EPA) Proposed Stormwater Rule

Currently, EPA’s stormwater rules only apply to these projects:

1. Major industrial facilities

2. Medium and large city municipal separate storm sewer systems, and

3. Construction sites that disturb five or more acres.

EPA’s proposed stormwater rules would apply to:

1. Major industrial facilities,

2. Small, medium, and large city separate storm sewer systems, and

3. Construction sites that disturb one or more acres.

Under current projections, the proposed rule would become final in March, 1999.

New municipal responsibilities under the proposed EPA rules

Under the EPA’s proposed "Phase II regulations" (Proposed Regulations for Revision of the Water Pollution Control Program Addressing Stormwater Discharges; Proposed Rule, 40 CFR Parts 122 and 12) permitting requirements will extend to many Maine municipal separate stormwater systems. The population criteria that will draw in Maine municipalities is a population of at least 10,000 and a population density of 1,000 people per square mile or greater. These are Bureau of Census "urbanized areas." The proposed rule would automatically designate some or all of the area in the following Maine cities and towns as small municipal separate stormwater systems" subject to the rule: Auburn, Bangor, Berwick, Brewer, Cape Elizabeth, Eliot, Falmouth, Gorham, Kittery, Lebanon, Lewiston, Lisbon, Old Town, Orono, Penobscot Indian Nation, Portland, Sabattus, Scarborough, South Berwick, South Portland, Veazie, and Westbrook.

Additionally, states may designate individual sources or small municipal separate storm sewer systems located outside of urbanized areas. Federal regulation of these municipal systems will mean that they must have an operating permit. Requirements for this permit include a stormwater management program and minimum control measures.

Stormwater management program

Under the proposed EPA rules, municipalities would be required to develop, implement, and enforce a stormwater management program designed for maximum reduction of the discharge of pollutants from the system. EPA’s term of art is "maximum extent practicable." Effluent limitations are achieved through implementation of best management practices (BMP’s) that are incorporated into the program. BMP’s must be designed to satisfy technology requirements, including reductions of pollutants to the maximum extent practicable, and water quality-based requirements of the Clean Water Act. Implementation of the BMP’s consistent with the stormwater management program and the permit provisions will constitute compliance with the standard of reducing pollutants to the "maximum extent practicable."

Minimum control measures

Under the proposed EPA regulations, minimum control measures required for municipal stormwater permits would consist of:

1) Public education and outreach on stormwater impacts.

The proposed rule envisions distribution of educational materials provided by the state or EPA covering topics such as proper septic system maintenance, garden runoff, and public involvement in restoration activities. Commercial, industrial, and institutional entities are to be provided with educational materials that address their contribution to the problems, for instance, the impact of grease clogging storm drains and oil discharges.

2) Public involvement/participation.

The public is to be included in developing, implementing, and reviewing the stormwater plan.

3) Illicit discharge detection and elimination.

A storm sewer system map, showing the location of major pipes, outfalls, and topography must be developed and maintained. Through municipal ordinance, order, or similar means, illicit discharges into the storm sewer system must be prohibited, and the prohibition must be enforced. A plan to detect and address illicit discharges must be developed and the citizenry informed of the hazards associated with illegal discharges.

4) Construction site stormwater runoff control.

For all construction activities within the small municipal separate stormwater system that disturb one acre or more, the municipality must develop, implement, and enforce a program to reduce pollutants. Through ordinance or other regulatory mechanism, erosion and sediment must be controlled to the maximum extent practicable under State or Tribal law. Construction site operators must be required to implement appropriate BMP’s.

5) Post-construction stormwater management in new development and redevelopment.

Municipalities would be required to develop, implement and enforce programs to reduce pollutants once construction has ended. Municipalities would establish requirements for the use of cost-effective BMP’s that minimize water quality impacts and attempt to maintain pre-development runoff conditions.

6) Pollution prevention/good housekeeping for municipal operations.

Municipalities would have to develop and implement cost-effective operation and maintenance programs designed to prevent or reduce pollutant runoff from municipal operations. Municipal employees must be trained to prevent and reduce stormwater pollution from government operations such as park and open space maintenance, fleet maintenance, planning, building oversight, and stormwater system maintenance.

How will this play out in Maine?

Maine does not currently regulate municipal separate storm sewer systems. Some problems inherent to municipal separate storm sewer regulation, either on the state or federal level include:

• Many municipalities are unaware of the scope of their responsibility for stormwater runoff.

• The municipal agency responsible for obtaining permits is not al ways known (public works authority, highway department, flood control authority).

• Many stormwater systems are on private property and even locating all discharge points is a major job.

• Municipalities will also be responsible for locating, sampling and imposing controls on every industrial facility that discharges stormwater into a municipal collection system.

• The urban/urbanized area approach is not as meaningful in Maine as in more urban states.

What will this cost, and who will pay?

Title II of the Unfunded Mandates Reform Act of 1995 establishes requirements for federal agencies to assess the effects of their regulatory actions on State, Tribal, and local governments and the private sector. EPA generally must prepare a written statement, including a cost-benefit analysis, for the proposed and final rules that may result in expenditures to State, Tribal and local governments.

As required, EPA determined that its proposed rule contains a federal mandate that may result in expenditures of $100 million or more in any one year for State, Tribal and local governments or the private sector. EPA also assessed the "social costs" of the proposed regulation to range from $141 million to $878 million annually.

The wide range of numbers calculated by EPA suggests that the cost assumptions are less than reliable. As a result of its required analysis of the potential economic impact of the proposed regulation on "small entities," EPA certified that "today’s proposed storm water rule will not have a significant economic impact on a substantial number of small municipalities." It is difficult to reconcile this EPA claim, given the apparent scope of the impending federal mandate in the area of stormwater management.