Know Your Role
Embedded Files
Identifying NPDES Violations
Identifying NPDES Violations
Go through the sections below.
Go through the sections below.
Identifying Illicit Discharges
Identifying Illicit Discharges
Municipal staff must investigate potential illicit discharges within its jurisdiction. Staff may be notified of illicit discharges by field observations, public complaints, or referrals from other agencies.
To investigate an illicit discharge, you must be well-versed in identifying them. In short, most discharges to the storm drain system--outside of a handful of exceptions we will discuss later--are considered illicit. Think of the mantra, "Only rain in the drain". Common illicit discharges include the following:
Vehicle washing. (Although residents are allowed to wash vehicles with discharge to the storm drain system, businesses--and municipalities--cannot.)
Sewer overflows from blocked sewer lines. Smaller overflows from laterals on private property are more common than overflows from public main lines.
Broken water lines.
Concrete washout from construction projects.
Tracking of sediment into the street from construction sites.
Review the presentation below of common illicit discharges.
Exempt Discharges (Authorized Discharges to the Storm Drain System)
Exempt Discharges (Authorized Discharges to the Storm Drain System)
As you might expect, some discharges are authorized by the Municipal NPDES Permit to enter the storm drain system. They include:
Uncontaminated stormwater
Emergency firefighting flows
Natural flows, like natural rising groundwater.
Other discharges are authorized if certain conditions are met. The conditions to be met in all cases include minimizing the flow, clearing debris from the flow path, and ensuring the discharge is clear (not turbid). They include:
Residential and non-profit (charity) car washing.
Irrigation runoff.
Fire sprinkler testing flows.
Pooled stormwater.
Pool and fountain discharges. Additional conditions: <0.1 ppm chlorine, no added chemicals.
There are also many types of discharges that require coverage under another NPDES Permit, separate from the Municipal NPDES Permit. Common examples include discharges from dewatering groundwater from construction sites, as well as discharges from water purveyor systems and water treatment plants.
Review the presentation on "authorized" discharges.
Identifying Stormwater BMP Deficiencies
Identifying Stormwater BMP Deficiencies
Recall that stormwater BMPs include any practice that prevents or reduces stormwater pollution. BMPs are needed when there is an activity that is generating pollutants that could discharge in a rain event. Typical activities that generate stormwater pollutants include industrial/commercial facility operations, municipal O&M activities, and construction site operations. BMP deficiencies occur when the facility operator has insufficient practices in place to prevent stormwater pollution. They include:
Uncovered waste material exposed to precipitation
Uncovered raw materials exposed to precipitation
Onsite spills and leaks exposed to stormwater
Review the presentation below of stormwater BMP deficiencies.
Stormwater BMPs: How Much is Enough?
Stormwater BMPs: How Much is Enough?
Most of the time, identifying BMP deficiencies is straightforward. However sometimes it can be a bit more difficult. Difficulties arise when you are not sure 1) whether an activity is generating pollution, and 2) whether existing BMPs are insufficient in preventing stormwater pollution. For example, say there is one piece of trash on the ground outside of a food facility, and the facility operator already cleans the property once a day. Is this a BMP deficiency by the facility operator? What if there are 10 pieces of trash on the ground, and cleaning occurs once a week? Where do you draw the line? Deep thoughts.
The point of the above example is not to deter you from identifying and resolving BMP deficiencies! It is just to let you know that sometimes the job can get a little subjective. That is the nature of stormwater pollution prevention. And it is addressed by using best professional judgement. If you feel that you do not have that best professional judgement, that is OK: Most municipalities have staff on-hand separate from Code Enforcement--either in-house or contracted--that are experienced in NPDES Permit inspections. A good approach may be to partner with--or defer to--them. Specific protocol is up to your Division/Department.
Page updated
Report abuse