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If your California facility is in Exceedance Response Action (ERA) Level 1, then you should be concerned about ending up in ERA Level 2 at the end of the stormwater year (July 1, 2017). It is only half way through the 2016-2017 reporting year, and industrial facilities are already finding themselves having stormwater exceedances that will land them in Level 2. Many facilities were anxious to collect stormwater samples from the first storm event of the year, concerned that they would miss out on the opportunity and not be in compliance with the new Industrial General Permit (IGP). Luckily, mother nature has been generous with rain this season allowing most California facilities under the IGP to sample the required two Qualifying Storm Events (QSE) in the first half of the reporting year (July 1st-December 31st). Unfortunately, for some facilities that sampled that first storm event this year, they ended up with terrible stormwater sample results that will push them into ERA Level 2 for the 2017-2018 reporting year. This can happen through instantaneous exceedances or high averages that are impossible to get below the annual Numeric Action Level (NAL). Even though a facility is required to sample four (4) times a year, that does not mean a facility must stop at four (4) samples. In fact, facilities are allowed to sample more than four (4) times a year. Sampling more than the minimum number of storm events can improve your chances of bringing down your annual average below the NAL. This is where the law of averages can work in your favor if you can get your stormwater exceedances under control.


For example, the situation below shows Total Suspended Solids (TSS) results for four storm events.
Sample Location 1st Storm 2nd Storm 3rd Storm 4th Storm Average
SP-1 130 mg/l 110 mg/l 90 mg/l 80 mg/l 125 mg/l
SP-2 200 mg/l 170 mg/l 100 mg/l 120 mg/l
At the end of four sampling events this facility’s average TSS is 125 mg/l, which is greater than the annual NAL of 100 mg/l. However, the results are trending down (storm #3 and #4). Let’s look at what happens if the Best Management Practices (BMPs) improve and two more storm events are sampled.
Sample Location 5th Storm 6th Storm Final Average
SP-1 20 mg/l 30 mg/l 90 mg/l
SP-2 10 mg/l 20 mg/l
Tough? Yes! However, just because you had a rocky start to the year that doesn’t mean you still cannot stay out of Level 2.


We are constantly harping on facilities to improve on their Good Housekeeping!! It is simple, doesn’t cost much (other than time) and can make a major difference in your stormwater sample results. Likely good housekeeping can keep you out of Level 1 and 2, especially for TSS, oil & grease, and metal issues that are tied to particulates. Here are a few suggestions to help reduce your facility’s risk of entering Level 2:
  • Make sure that you are actively implementing Minimum Best Management Practices (BMPs), such as good housekeeping, spill and leak prevention, preventative maintenance and training!
  • Ensure that sampling is being conducted correctly by trained personnel.
  • If you have not already done so, find a Qualified Industrial Stormwater Practitioner (QISP) to complete your Level 1 Exceedance Response Action (ERA) Report, update your Storm Water Pollution Prevention Plan (SWPPP) and train your Pollution Prevention Team (PPT).
  • Understand the additional BMPs recommended by your QISP in your Level 1 ERA Report and actively implement them.
  • Replace any additional BMPs already implemented at the site that are beginning to degrade (i.e. wattles, filter socks, storm drain inlets, etc.)
  • If sample results are still exceeding NALs, evaluate effectiveness of BMPs and consult with your QISP on additional recommendations.
  • Keep a spreadsheet with your results and averages or use software to track your instantaneous and average exceedances.
  • Sample, sample, sample!! Sample as many QSEs as possible so that you can increase the possibility of lowering your average.

What Samples Count

There is some confusion around the wording of the IGP in regards to when sampling results will be included in the calculations for Level 2. Just to make it clear, the section of the permit that explains this is referenced below.
“Prior to the implementation of an additional BMP identified in the Level 1 ERA Evaluation or October 1, whichever comes first, sampling results for any parameter(s) being addressed by that additional BMP will not be included in the calculations of annual average or instantaneous NAL exceedances in SMARTS.” (General Permit for Storm Water Discharges Order 2014-0057-DWQ)
So the highlighted area is what is important. Dischargers (and some QISPs) were under the impression that results from their first sampling event would not be included in their calculations for Level 2 because it was before they implemented all of their additional BMPs. However if you read the highlighted section above it clearly states “whichever comes first” implying that any results after October 1st will be included in your calculations for Level 2. Almost all facilities’ very first stormwater samples were collected after October 1st. Therefore, these samples will be included in their Level 2 calculations. July 1st is right around the corner, do you know which direction you are heading? If not, you better get to work!

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