How to Take Samples—Water

Remember, analysis is based solely on the sample provided. Improper sampling will result in misrepresentation of values.

General Sampling Instructions

For most water tests, follow these steps when collecting a sample. Take the sample close to the pump, before the water goes through a treatment system (unless testing the treatment system). Run the pump for approximately 2-3 minutes. Removed the screen or aerator from the faucet. Allow the water to run approximately 5 minutes to clear the line. Take the sample midstream of the sample flow. Do not touch the inside of the collection bottle, the opening or inside of the cap. Fill the sample bottle to the neck and cap tightly. Sample bottles not properly filled will not be analyzed. Samples should be received in the laboratory with a temperature of 6°C (43°F) or below by Minnesota Department of Health standards. Samples received above that will have the temperature on the report flagged as such.


How to Collect a Drinking Water Sample for Bacterial Analysis

Your sample bottle (height of 4") has been sterilized. For accurate testing, it is important to keep it free from contamination. If you accidentally contaminate it, please return it for another sterile bottle. Do not boil the bottle or put anything inside it except your sample. Select an outside faucet if testing the well. If testing household piping, select a faucet from a kitchen or utility sink. Bathroom faucets are not recommended. Remove any filter or screen from the tap. Disinfect the faucet with bleach or a flame before taking the sample. Outside faucets may also be flamed with a hand-held torch if they are not made of plastic or rubber. Turn on the cold water and let it run for at least 5-10 minutes. Adjust the water to produce an even flow. Remove the cap from the sample bottle. Do not set the cap down or touch the inside of the cap or bottle. Fill the sample bottle to the neck only. Do not let the faucet touch the mouth of the bottle. Carefully re-cap the bottle and immediately mail or deliver the sample. Certified samples must be analyzed within 24 hours of the time you took the sample. Both Colilert and Membrane methods are certified by the Minnesota Department of Health. The Colilert coliform method gives results the next day, where the membrane method will take an extra two days if any growth is found. Samples must be received by 12:00 noon on Fridays to be processed. Any "RUSH" samples must use Colilert method for analysis. Keep your water sample out of the sunlight and heat. Samples should be received in the laboratory with a temperature of 6°C (43°F) or below by Minnesota Department of Health standards. Samples received above that will have the temperature on the report flagged as such.


Collecting Other Samples

Lead and Arsenic Samples
If testing interior piping, select a faucet from a kitchen or utility sink. Bathroom faucets are not recommended. Remove any filters or screens from the tap. The water must not be used for at least 6 hours, preferably standing in the line overnight. Place the container under the faucet and slowly turn on the COLD water. Do not purge the line or use the hot water side. Catch the first flow from the faucet and fill the container until just below the neck with allowance for preservation. Do not overflow the sample bottle. Cap the bottle and record the sample date and time.

Lakes, Rivers and Reservoirs
Select a spot where a representative sample can be taken. Remove the cap from the sample bottle from below the surface to avoid introducing surface scum. Position the mouth of the bottle into the current, away from the hand of the collector. Do this in a continuous sweeping motion, extending the mouth of the bottle into the water and sweeping to a depth of approximately one-two feet. Continue the sweep to the water surface and above. Carefully pour off the water above the neck of the bottle, and then replace the cap without touching the mouth of the bottle. Cap the bottle and record the sample date and time. Samples should be received in the laboratory with a temperature of 6°C (43°F) or below by Minnesota Department of Health standards. Samples received above that will have the temperature on the report flagged as such.


Bottle Requirements

Small (Sterilized) 4" Bottle

**Each bullet requires one small bottle

  • Coliform (Total, E.coli or Fecal)

  • Nitrate and Coliform

  • Arsenic

  • Lead

  • Iron Bacteria

  • Sulfate Reducing Bacteria

  • Fluoride

  • Minerals: Ca, Mg, K, Na, Cu, Fe, Mn, Zn

  • Solids


Large 6" Bottle

**Requires one large bottle

  • Water Suitability Package

    • Nitrate, Ca, Fe, Mn, Mg, Na, Cu, Chloride, Sulfate, pH, Hardness, TDS and Conductivity

  • Municipal/Watershed Testing

    • Call for bottle requirements

Miscellaneous

  • Water Toxicity (one large bottle and two small bottles)

    • Large: Copper, Fluoride, Nitrate and Nitrite

    • Small: Lead

    • Small: Arsenic

  • Water Softener Performance (two large bottles)

    • One bottle labeled: Before

      • Ca, Fe, Mn, Mg, Na, Sulfate, pH, Hardness, Conductivity

    • One bottle labeled: After

      • Ca, Fe, Mn, Mg, Na, Sulfate, pH, Hardness, Conductivity













Stearns DHIA Laboratories
825 12th Street South, PO Box 227
Sauk Centre, MN 56378-0227
320.352.2028 · 800.369.2697
Fax 320.352.6163 · Email

 

Hours
Monday-Friday: 8AM-4PM
Front Entrance Drop-Off Open 24 Hours
Refrigerator Available for Water, Milk,
and Wet Feed Samples