Storm Water Sampling Made Easy

Iowa auto salvage yards with more than 250 vehicles in the yard are required to sample storm water (rain) runoff for parameters listed below.  Collect and submit rainfall samples to a laboratory for analysis annually.

Retain a copy of the report with the Storm water Pollution Prevention Plan (SWPPP). It is not required to submit the report to the regulatory agency but it must be maintained on-site in the event an inspector requests to see it. There are no regulatory limits on the values of test results, only that the samples are taken and analyzed.

Any analytical laboratory with the capacity to test storm water may conduct the testing procedures. An arrangement has been made with TestAmerica to conduct the samples through Sue Schauls that will ensure accuracy in the testing procedures including using the parameters required and reporting data in the required formats.

Storm Water
Collect the Sample

Collect a representative grab sample and a composite sample of rain water flowing off the property (outfall location). Download instructions in pdf.

In the first hour of a rainfall of significance (about 2 inches) collect a half gallon of water to be used as the Grab sample and the first small amount for the Composite sample. Fill all of the bottles marked GRAB in the storm water kit (cooler) received from Sue/TestAmerica or another laboratory.

Fifteen minutes later collect another small amount (2-4 cups) of runoff water and add it to the remaining water from the Grab sample.

Fifteen minutes later collect another small amount of runoff water (even if it has stopped raining) and add it to the other collected water. If you have half gallon of water then fill all the remaining sample bottles in the kit. Otherwise collect more water then fill the bottles.

Deliver or ship the collection kit to TestAmerica (or another laboratory) using the included shipping label and prefilled CHAIN OF CUSTODY. You need only to fill in your facility name/address, all other documentation has been taken care of by Sue, including billing.

(An ice bag is included)

In about two weeks you will receive a laboratory report and a data interpretation from Sue. The cost to an Iowa Automotive Recycler member is $320.

1) A grab sample is a one-time sample that represents the discharge in the beginning of the rainfall event. The grab sample must be taken in the first hour of the discharge.  The laboratory recommends taking a 3000 milliliters (ml) sample (about two quarts) to ensure enough water to perform all tests is available. The seven parameters tested will cost approximately $195.

2) A time-weighted composite sample is taken at timed intervals in equal amounts. The composite sample is taken as a combination of (at least three) small samples (called aliquots) taken throughout the duration of the discharge (for at least three hours), with each small sample being separated by at least 15 minutes.  The laboratory recommends taking 300-1000 ml at each sample so that the total amount of the composite sample is 3000 ml (about two quarts) to ensure enough water to perform all tests is available. The five parameters tested will cost about $125.

Both sets of samples, the grab and the composite, must be tested for five parameters:
  • five day biochemical oxygen demand (BOD);
  • chemical oxygen demand (COD);
  • total suspended solids (TSS);
  • total Kjeldahl nitrogen (TKN);
  • total phosphorus;
The grab sample must be tested for two additional parameters:
  • oil and grease;
  • pH;
The Sample Collection Kit will include:
2 Large Amber Glass Sulfuric Acid (H2SO4) Preserved for Oil & Grease GRAB sample
2 Quart Plastic - NO TREATMENT
One each for BOD & TSS Composite & BOD, TSS & pH Grab samples
2 Quart Plastic - Sulfuric Acid (H2SO4) Preserved
One each for COD, TKN, PO4 Composite & COD, TKN, PO4 Grab samples

Automotive salvage yards have particular concerns for adding pollutant to storm water runoff due to the sheer number of vehicles present in a yard at any given time. Effective pollution prevention of these storm water pollutants is accomplished through choosing the most applicable Best Management Practice (BMP) as identified in the Storm Water Pollution Prevention Plan (SWPPP) developed as part of the storm water permit requirements.

The Storm Water Permit Process –Six simple steps to compliance
1) Complete a Notice of Intent (NOI) to discharge storm water. Iowa DNR Form 542-1415.
2) Run a public notice in two widely distributed local newspapers.
3) Prepare and maintain a Storm Water Pollution Prevention Plan (SWPPP).
4) Pay the applicable fee to the Iowa DNR.  $300 per salvage yard for a three-year permit.
5) Begin annual inspection of the facility and provide training to employees.
6) Annually monitor the storm water runoff by collecting samples for laboratory analysis.