The United States Environmental Protection Agency (EPA) was created to protect the environment. The EPA enforces regulations based on laws passed by Congress. President Nixon created the EPA by signing an executive order in 1970. In 1972 the Clean Water Act (CWA) was passed by Congress and became Federal Law. The CWA authorizes the creation of the National Pollutant Discharge Elimination System (NPDES) in each state.
The NPDES is delegated to the State of California and is run by the State Water Resources Control Board (SWRCB) and the nine Regional Water Boards. The Industrial General Permit (IGP) was adopted by the SWRCB on April 1st, 2014 and went into effect on July 1st, 2015. The IGP provides regulations regarding storm water compliance to the industrial business sector. The IGP designates a list of Standard Industrial Classification Codes (SIC Codes) that are subject to the IGP. Industrial businesses in those SIC Codes must apply for a Notice of Intent (NOI) to receive a WDID Number and be permitted under the IGP. The IGP is an NPDES Permit issued by the SWRCB.
When it rains, each industrial business subject to the IGP must test the rain water running off their site and into the drains that lead to the ocean or other body of water. The water running off these sites, into the drains, is called Stormwater Run-off. It can also be called a discharge. When the storm water runs off an industrial site, you can say the site is discharging storm water run-off. The discharged water must be tested by taking water samples and sending them to a lab for testing. When the sample results are analyzed, they will be assigned a numeric value for each parameter that is tested.
Possible common parameters include: Total Suspended Solids (TSS), Oil & Grease (O&G), pH, Iron (Fe), Zinc (Zn), Lead (Pb), Copper (Cu), Aluminum (Al).