In general, most sampling procedures for drinking water testing are the same. However, the steps required for some chemical analysis will vary for different tests. This is why it is always a good idea to contact the laboratory where you plan to have your drinking water tested before you collect the sample to find out what specific instructions you may need to follow. You can download a listing of certified labs for water testing in Montana, stop by our office, or give us a call at 582-3148 to obtain the list. Timeliness and cleanliness are important when collecting any water sample. Below are some helpful hints that apply to almost all water collection procedures:
Use a certified laboratory to run the test.
Use the sterile collection bottles available from the lab and not your own bottles to take a sample. Most labs will only accept samples taken in their own collection bottles.
Complete all the forms and fill out all labels the lab requires to process the sample.
In most cases, a water sample must be submitted to the lab within 48 hours of collection. And, in some cases, the water sample must be kept cold prior to testing.
Take care to prevent anything but the water from contacting the inside of the sample bottle or cap. Careless sampling prevents accurate test results.
Taking the Sample
1. Select a convenient sampling point at a faucet. An outdoor faucet closest to the well is preferred. Remember, if you have a water softener or treatment system installed at your home, the water sample must be collected before it goes through these systems.
2. Remove any screen or aerator from your faucet.
3. Run the cold water faucet for at least 20 minutes at a high flow rate before collecting the sample. This is critical! This flushing is done to clear water that has been standing in the pipes and pressure tank and bring in "fresh" water from the well before sampling. Incomplete flushing may result in an inaccurate measurement in the laboratory.
4. Without turning the faucet off, reduce the flow rate at the faucet and open the sample bottle. Be sure not to touch the inside of the sample bottle or lid.
5. Fill the sample bottle and replace the cap. Make sure the cap is on tight.
6. Refrigerate the sample until you take it to the lab. Transport the sample in a cooler to the lab. Remember, some tests have holding time limits for analysis, so you should get the sample to the testing laboratory as soon as possible after collecting it for best results.
Testing for Volatile Organic Chemicals
When collecting a water sample to be tested for volatile organic chemicals (solvents, etc.) the following additional steps should be followed:
1. Reduce water flow to prevent excess air in the sample.
2. Fill the sample bottle to almost overflowing to remove all air fromfthe bottle.
Testing for Pesticides, Herbicides and Petroleum
Samples for pesticide testing must be taken so they will not deteriorate or become contaminated before reaching the lab. Contact the lab testing your sample for complete instructions and a collection kit. Specific steps needed when testing for pesticides include:
1. Collect sample ONLY in the amber-colored bottle provided. Dark glass prevents light from degrading the sample.
2. DO NOT RINSE the sample container! It contains a preservative necessary for proper analysis of your sample.
3. Take the sample from a COLD water tap indoors. Do not take samples from a hose.
4. Remove the faucet aerator.
5. Allow the water to run for 3-4 minutes before sampling.
6. Fill the container full to the neck and cap tightly with the Teflon-coated lid provided by the lab. This special lid prevents false positive results caused by certain plastics.
7. Keep the sample refrigerated and submit to the lab within 48 hours. If shipping the sample, pack the sample in ice and ship in a styrofoam or other insulated container. Many laboratories will provide ice packs and shipping container for you.
Test Results
If test results show an unacceptable contamination level, you should seek the advice of a professional. In many cases, a second test will be taken before recommending possible treatments.
Test Records
Keep a record of your water tests including the date and the test results. This will allow you to compare recent test results to previous results and is an easy way to identify problems you may not have noticed. Many real estate transactions require water tests and a record of results can be beneficial. Records results also support damage claims from outside contamination, such as from chemical spills or leaks.
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