EHB Decision Supports DEP Nitrates Methodology

October 2010Newsletters In the Zone

On August 31, 2010, Pennsylvania’s Environmental Hearing Board (EHB) rendered an adjudication clarifying calculations relative to the Nitrate Mass Balance Equation (MBE) used when determining groundwater impacts caused by the installation of on-lot septic systems.

High levels of nitrates in drinking water are believed to potentially cause health issues for children and pregnant women.

The EHB sustained the Department of Environmental Protection’s disapproval of a land use development planning module that provided for use of on-lot sewage disposal. The EHB found the Department’s approach in analyzing the plaintiff’s planning module and denying it using its MBE was appropriate.

Among other things, the plaintiff unsuccessfully challenged the Department's numerical inputs to the MBE calculations. Namely, the applicant argued the gallons of wastewater produced by a typical home are significantly lower than those proposed by the Department due to population trends indicating reductions to the number of household occupants. Additionally, the concentration levels of the effluent produced were called into question.

Furthermore, the plaintiff attempted to make the case that a change in land use from an actively farmed parcel into a residential development consequently produces lower levels of nitrate contribution to the groundwater.

The EHB found the Department’s numerical inputs to its MBE were all appropriate and reasonable under the circumstance and well-supported by the evidence. In addition, the EHB held the mitigating factors articulated by the plaintiff were rightfully ignored by the Department in reviewing the applicant’s module.

The result of this EHB decision is to validate the methodology the Department has used in evaluating planning modules proposing on-lot septic systems.

For more information, please contact Clair E. Wischusen at 215.918.3559 or [email protected]