EPA’s Effluent Guidelines: The Final Rule

Jan. 1, 2010

It’s finally here: The EPA has published in the Federal Register the long-awaited final “Effluent Guidelines for Discharges from the Construction and Development Industry”-something many in the ESC industry have been waiting for, either hopefully or with dread, since last December’s draft guidelines were published.

When the guidelines go into effect, there will be-for some construction sites, at least-a numeric effluent limit for discharges such as stormwater runoff. That limit is 280 nephelometric turbidity units (NTU) for sites of 10 acres or more. This requirement is a big change from the current rules, which require only visual inspection to monitor construction-site discharges. (Some state permits have gone beyond current EPA rules and incorporated numeric limits into their permits, however.)

The 280-NTU limit is very different from the one in draft guidelines published a year ago, on which the EPA received numerous public comments. The draft proposed a limit of only 13 NTU, which is below background turbidity in some areas. Developers were worried about the extreme costs of meeting such a low number, and some even within the erosion control industry commented that under certain circumstances, getting the water that clear might deprive downstream ecosystems of needed sediment-doing more harm than good in some environments. Under the draft guidelines, this limit would have applied only to sites disturbing 30 or more acres-three times the size of those covered under the current rule-which also had an R factor of at least 50 and a clay content of at least 10%.

Sites covered under the new rule will be required to take water samples throughout the day, and the average of all the measurements must not exceed 280. (An individual sample above that level is acceptable as long as the daily average is 280 or less.) If a storm larger than the local two-year, 24-hour storm occurs, the limitation doesn’t apply that day.

The new guidelines also require sites that are not subject to the numeric limit to incorporate best management practices, as is required now, for erosion and sediment control. The EPA has made changes, however, to its non-numeric effluent guidelines to make them more applicable to all construction sites. These include removing the specific requirements to minimize the amount of exposed soil at one time, to preserve natural vegetation, to provide and maintain natural buffers around surface waters, to establish temporary or permanent vegetation, to divert stormwater runoff from disturbed areas of the site, to establish and maintain perimeter controls, and to use wheel wash stations, among others. You can see a detailed list, as well as the reasons these items were not considered applicable to all sites, in section X.B of the final rule, available here.

It’s important to note that the rule does not take effect immediately-although many are certainly planning for it now. The rule will go into effect in phases: within 18 months of its publication, sites disturbing 20 or more acres will have to begin monitoring and complying with the 280-NTU limit. Four years after the rule’s effective date, sites disturbing 10 acres or more will need to comply.

About the Author

Janice Kaspersen

Janice Kaspersen is the former editor of Erosion Control and Stormwater magazines.