MSU Extension logo

Michigan State University Extension
Home Maintenance And Repair - 01500568

How to Take a Water Sample

Water may appear clear and pure, but water from wells or other sources may contain dissolved minerals and other substances. Generally, ground water provides a good supply of safe water, that doesn't need much treatment. If you are a private well owner, you need to test your water supply to insure the well provides safe, high quality water.

With the advice of your county Health Department or Cooperative Extension office, decide what tests are needed for your water supply. After selecting the tests, choose a lab to test the samples.

Steps required for taking a water sample will vary for different tests. Timeliness and cleanliness are important when collecting any water sample. Use the sterile collection bottles the lab sends you and not your own bottles to take a sample. Labs often will only accept samples taken in their collection bottles. Also complete all the forms the lab requires to process the sample.

A water sample needs to be submitted to the lab within 48 hours of collection. In some cases it must be kept cold prior to testing. Care must be taken to prevent anything but the water from contacting the inside of the bottle or the cap. Contaminants are often present in small amounts. Careless sampling prevents accurate test results.

General Procedures

For most water tests, follow these steps when collecting a sample: How to take a water quality test images(Vis. 1)

- Take the sample close to the pump, before the water goes through a treatment system.

- Do not take the sample from a swing-type faucet. Inspect the faucet for leaks. Select another faucet if there is leaking.

- Remove the aerator.

- Disinfect the faucet with bleach or a flame.

- Run the water several minutes to clear the line.

- Take the sample midstream. Do not touch the sides of the collection bottle, the opening or inside of the cap.

- If needed, store the sample in the refrigerator before taking to the lab.

- Submit the sample within 48 hours of collection.

- Transport the sample in a cooler or ship in an insulated container.

Some tests, such as lead, require the water stand in the pipes overnight before taking a sample. Again, follow the instructions provided by the lab or your Health Department.

Testing for Volatile Organic Chemicals

When collecting a sample to be tested for volatile organic chemicals these additional steps should be followed:

- Reduce water flow to prevent excess air in the sample.

- Remove all air from the collection bottle by filling it to almost overflowing. Again, timeliness and cleanliness are extremely important to prevent false results.

Testing for Pesticides

Samples for pesticide testing must be taken so they will not deteriorate or become contaminated before reaching the lab. Contact the lab testing the sample for complete instructions and a collection kit. Specific steps needed when testing for pesticides include:

- Collect the sample only in the amber colored bottle provided. The dark glass prevents light from degrading the sample.

- Cap the bottle with the Teflon coated lid. The special lid prevents false positive results caused by certain plastics.

- Keep the sample refrigerated, preferably 35 degrees to 38 degrees, and submit it to the lab within 48 hours. If shipping the sample, pack the sample in ice and ship in a Styrofoam or other insulated container.

Test Results

If test results show an unacceptable contamination level you should seek the advice of a professional. In most cases a second test will be taken before recommending possible treatments.

Test Records

Keep a record of your water tests. The record should include the date and the test results. Comparing recent test results to previous test results might point out problems you may not have noticed. Water test records are often needed for property sales. Records also support damage claims from outside contamination, such as from chemical spills or leaks.

For Further Information: for further information on water testing or possible contamination suspected in your area, contact your local Health Department or county Cooperative Extension office.


This information comes from Purdue Extension bulletin WQ3, How to Take a Water Sample.

Return to main page

This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company.

MSU is an affirmative-action, equal-opportunity employer. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

This information.was reviewed as of June 2008.  For more information about the contents please contact for webpage problems .