First Quarterly Stormwater Sampling Deadline of 2025 Approaching

If your facility is required to conduct quarterly stormwater sampling in order to comply with the New York State Department of Environmental Conservation (NYSDEC) Multi-Sector General Permit (MSGP) for Stormwater Discharges Associated with Industrial Activity (GP-0-23-001), or if your facility is covered under an individual State Pollutant Discharge Elimination System (SPDES) permit that regulates stormwater discharges, now is the time to complete the sampling if you have not already done so! The stormwater sampling deadline for this quarter is March 31.

How Is Sampling Completed?

Samples must be collected from the outfalls designated in the permit which applies to your facility. To ensure that you do not miss the sampling deadline, it is best practice to complete sampling early in the quarter, in order to avoid difficulties posed by dry weather and unforeseen scheduling difficulties.

Once the stormwater samples are collected, they are submitted to a certified laboratory for the required analyses. The analytical results reported by the laboratory are then evaluated and used to prepare and file your quarterly monitoring report.

Why Is Early Sampling Important?

Stormwater samples need to be collected during a “qualifying storm” event, which produces greater than 0.1 inches of rainwater. This might not sound too difficult, since it rains often enough, but the truth is, it always seems to rain when you don’t want it to, and conditions are dry when you need rain the most. This is why it is highly encouraged to focus sampling efforts early in the quarter when qualifying storm events are forecasted. Waiting until the last week of a quarter may result in no rain at all that week, and even if there is a qualifying storm, you still need to get the samples to the lab for analysis.

With less than one week until the deadline, the time to get this sorted is nearing an end. If you are one of the late samplers this quarter, make sure to prioritize stormwater sampling during the early part of the second quarter to avoid stress and uncertainty.

If your facility has yet to complete its required sampling, or if you are unsure whether this applies to you, call Walden at 516-980-5508. Our qualified scientists and engineers can assist you with all of your stormwater compliance needs.