Stormwater Sampling Primer

Only trained, capable, and ready members of pollution prevention team (PPT) should undertake the stormwater sampling.  Below is general overview of the most important features of the stormwater sampling requirements.

Qualifying Storm Event Criteria

• The depth of the storm must be greater than 0.1-inch accumulation.
• The storm must be preceded by at least 72 hours of dry weather.

Collecting Stormwater Samples

• The grab samples must be collected within the first 30 minutes of a discharge.
• pH has a 15-minute holding time; therefore, the sample must be analyzed within 15 minutes of collection.

After the samples have been collected

• Place the samples in a sturdy cooler partially filled with ice. Samples should be kept at approximately 39°F (4°C) until the cooler is delivered to the lab.
• Keep the completed chain‐of‐custody with the cooler/stormwater samples.

Is your Stormwater Pollution Prevention Plan (SWPPP) prepared and implemented correctly? The SWPPP must accurately reflect all facility operations that generate industrial stormwater discharges and must be signed, dated and available for agency inspection.

It is important to conduct annual stormwater team refresher training so that everyone on your stormwater team is on the same page and knows their roles when it comes time to sample. Implementing correct sampling techniques and documentation is very important for regulatory compliance and to avoid potential citizen suits (refer to §505 of the Clean Water Act (CWA)).

Contact Sam Joshi at (215) 389-2811 to discuss how your facility stormwater compliance program can be improved.