The Maryland Department of the Environment (MDE) modified the County's Permit effective January 26, 2004 to add six small localities as co-permittees for coverage under the Phase 2 of the National Pollutant Discharge Elimination System (NPDES) MS4 Permit Program.  There were five municipalities: the Towns of Chevy Chase, Kensington, Poolesville, and Somerset,  and Chevy Chase Village; and one special tax district,  the Village of Friendship Heights.

The County continues its systematic, watershed-based, assessments to identify priority subwatersheds and maximize water quality benefits using efforts that are definable and the effects of which are measurable.  The County program integrates biological monitoring and physical habitat assessments with stormwater retrofit and stream restoration opportunities, water quality discharge law enforcement, and public outreach and involvement. This approach leads to pollution prevention and project construction efforts that provide water quality benefits to the maximum extent practicable.

The Permit requires that Montgomery County submit each year a fiscal analysis of the capital, operation, and maintenance expenditures necessary for compliance.  The County proposes a budget of $12.9 million to comply with Permit requirements during FY06.  From FY05 to FY06,  the category with the greatest increase will be that for the Stormwater Maintenance Inspections and Facility Repairs.  The percentage of the  total budget increased from about 20% for FY05 to about 32% proposed for FY06.  This reflects an increase in the number of structures being taken into the program and number of repairs being completed.

The Permit requires the County to annually submit estimates of expected pollutant load reductions as a result of its proposed management programs.  Due to a mapping discrepancy,  acres shown with stormwater management decreased by approximately 10% from 2003 to 2004.  Much of this apparently "lost" acreage was from redundant structures, either multiple on one site or in a series to one facility.  New loads reductions will be calculated for the next annual report when more accurate drainage area information will be available.  The most recent estimates showed that approximately 35.1% of all developed lands in the County had some form of stormwater management.  There was an estimated 8.4% reduction in TN and a 16.9% reduction in TP loadings in runoff due to those controls.

The MDE has previously commended the County’s substantial progress toward ensuring proper maintenance of stormwater management facilities, initiating pollution prevention at County-owned facilities, and for aggressively pursuing stormwater retrofit and stream restoration opportunities. The County’s efforts have been termed "exemplary" and "extraordinary" as it has successfully integrated water quality monitoring, public education and involvement, stormwater management facility inspection and maintenance, enforcement activities, and watershed protection and water resource policy development.