Best Management Practices (BMP) - Anything we do regularly to manage something (in this case stormwater) in the best way possible. More specifically, any policy, maintenance procedure, prohibition, or other management activity intended to prevent or reduce pollution. Some examples of BMPs are: treatment facilities to remove pollutants; operation and maintenance procedures; practices to control runoff, spills or leaks, waste disposal, and drainage from stored materials; erosion and sediment control practices; ordinances and rules.

Illicit Discharge - Anything entering the County's MS4 or other regulated waterbodies, directly or indirectly, that is not purely stormwater. There are some exemptions, such as firefighting activities, but these must be specifically listed in an ordinance or rule. Any discharge in violation of a NPDES permit is also considered an illicit discharge.

Measureable Goals - Specific quantifiable tasks a permittee agrees to accomplish to meet the BMPs it has chosen in its NOr.

Minimum Measures - The six basic requirements of NPDES Phase II permits.

Municipal Separate Storm Sewer System (MS4) - The publicly owned system of pipes, ditches, drains, ponds, and other man-made devices for handling stormwater. Two key points are (1) that the system has to be operated by a local government and (2) it has to discharge to "Waters of the US", "Waters of the State", or connect to another MS4.

The word "separate" means that it is separate from the sanitary sewer system which handles toilets, showers, etc. It distinguishes storm sewers from the old "combined" sewers that handle both types of water. We don't build "combined" sewers anymore, but they still exist in some older places. To protect the public health, combined sewers have to be regulated differently.

NPDES - National Pollutant Discharge Elimination System. This is the name given to the US EPA's water permitting programs (including stormwater, domestic wastewater, and industrial wastewater discharges).

Nonpoint Source Pollution - Nonpoint source (NPS) pollution, is pollution that comes from many diffuse sources. The opposite is Point Source pollution, like what would come from industrial and sewage treatment plants. Think of it just like the name, if you can point to the source (this pipe, or that lot of land) it's a Point Source, if you can't it must be NPS pollution. When water runs along the ground it picks up pollutants like dirt, chemicals, and trash, then dumps them into waterbodies or soaks them into the ground water. Imagine the path taken by a drop of rain from the time it hits the ground to when it reaches a river. Essentially, anything we put on the ground will eventually get into our waters.

NPS pollution is widespread because it can occur anytime and anywhere. Septic systems, runoff from streets and yards, construction, recreational boating, agriculture, forestry, grazing, altered stream channels, and degraded habitats are all potential sources of NPS pollution. Careless handling of wastes at home also contributes to NPS pollution.

Notice of Intent - The application to be covered under an NPDES generic permit. This is where a permittee lists its BMPs and Measurable Goals.

Stormwater Management Program - The program a local government develops to accomplish the tasks of the NPDES permit.