How to Collect Water Samples - Well and Household

Collecting your water sample the right way helps you get accurate results.

A sample collected the wrong way can show coliform bacteria in your water even when your water is safe. If that happens, you may have to pay for more testing. Follow each step below carefully.

Water Collection Steps

Step 1.Choose the right faucet

Use a faucet you normally get water from.

  • Use a faucet that does not swivel, if you can.
  • Remove any aerator or screen from the end of the faucet.
  • Do not use a faucet that leaks. Leaks can help bacteria grow.
  • If you use an outdoor faucet, remove any hoses or attachments.
  • Do not collect samples from fire hydrants or frost-free faucets.
  • Do not use a faucet if the water goes through a treatment device first, such as a carbon filter or water softener.
  • Do not dip the bottle into a reservoir or storage tank.

Step 2.Use only bottles from your lab

Use only sample bottles provided by the lab that will test your water. Bottles from Falls Community Health have a white cap with no markings.

  • Do not use a bottle if its cap has come off.
  • Do not rinse the bottle. The lab puts a chemical inside that is needed for correct test results.

Step 3.Keep the bottle closed until you fill it

The bottle is sterile, which means it is free of germs. Opening it early can contaminate it.

Step 4.Flush the line

Run water through the faucet for at least 2 to 3 minutes before you open the bottle.

  • If you are not sure the faucet is clean, wipe or spray it with household bleach or a sodium hypochlorite solution (100 mg NaOCl/L). Then run the water for another 2 to 3 minutes.
  • If the faucet mixes hot and cold water, run hot water for 2 minutes, then run cold water for 2 to 3 minutes.

Step 5.Fill the bottle

Turn the water down to a steady stream. Take the cap off the bottle and gently fill it.

  • Hold the bottle near the bottom.
  • Do not touch the inside of the bottle or the inside of the cap.
  • Do not set the cap down while you fill the bottle.
  • Be careful not to splash out the chemical tablet that is already in the bottle.
  • Fill the bottle only up to the neck. Do not let it overflow.

Any of these mistakes can contaminate your sample.

Step 6.Put the cap back on right away

Make sure the cap is tight so the bottle cannot leak.

If you drop the cap or think the sample may be contaminated, do not use it. Get a new bottle and collect a new sample.

Step 7.Fill out the data slip

Fill out the water testing data form as completely as you can.

Step 8.Send the sample to the lab right away

Mail or deliver your sample as soon as you collect it. The lab cannot accept samples older than 30 hours. After that, the water in the sample has changed too much to give correct results.

  • Mail your sample on the same day you collect it.
  • Plan so your sample arrives Monday through Friday.
  • Make sure it arrives at the lab by 4 p.m., so staff have time to set up your test.