Division of Environmental and Community Health

Maine Center for Disease Control & Prevention

A Division of the Maine Department of Health and Human Services

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Water Sampling and Testing

All public water systems are required to regularly sample and test their water to ensure that it meets federal and state drinking water standards, and is safe to drink. Without proper and timely sampling and testing, you cannot know the quality of the water you are serving.

NEW! Revised Total Coliform Rule

Drinking Water Testing Requirements

Each year in March, the Drinking Water Program generates and mails a list of annual drinking water testing requirements to all public water systems. If you have not received a copy of your testing requirements you can access your information online by clicking here. If you feel the testing requirements you have received are inaccurate, please contact your Public Water System Inspector. To view a report of compliance samples the Drinking Water Program has received and processed for your Public Water System, please click here.

Please remember the following guidelines when taking compliance samples:

A Sampling Quarter is the same as a Calendar Quarter. If you are required to sample within a specific Quarter, the sample must be taken within the Calendar Quarter.

Sampling Quarter Dates
1st Quarter January 1 - March 31
2nd Quarter April 1 - June 30
3rd Quarter July 1 - September 30
4th Quarter October 1 - December 31
  • Carefully follow the directions for collecting the sample and completing the paperwork.
  • Make sure to always include your System name and PWSID# on all sample sheets/correspondence.
  • When you take your sample to the certified laboratory make sure they know that the sample(s) is for drinking water compliance and that the results must be sent to the DWP by the 10th day of the month following the sample collection period.
  • Verify with your lab that your results were submitted to the DWP on time.
  • It is your responsibility that water test results get submitted to the DWP by a certified laboratory.
  • Bacteria samples must be taken within the distribution system at the pre-approved locations you submitted on your bacteria sample site plan. No compliance bacteria should be collected at the source unless it is the only public access to the water.
  • For small water systems that have no treatment, the entry point sample(s) can be taken from the first tap within the distribution system.
  • Be sure to contact your Compliance Officer before testing for Endothall or Diquat, to be sure that you are required to test for them. Diquat, Asbestos, and MPA (Microscopic Particulate Analysis) are only analyzed in laboratories outside the state of Maine. Please contact the DWP if you are required to test for any of these contaminants.

Certified Laboratories

The Laboratory you select must be certified to perform the tests you want to run on your water samples. You can visit the Laboratory Certification page to obtain a list of all Maine certified commercial laboratories or to ensure the lab you have chosen is certified to perform the tests you want to run. You may confirm what tests are done by a laboratory or ask any other questions regarding laboratory quality by calling (207) 287-1929 or by emailing the certification officer at

Sampling Frequently Asked Questions (FAQs)
Why is sampling important? When do I need to sample? What is a sampling quarter? What happens if I miss a sample? What are the sample collection locations and hold times by test? How is a sample collected? What is a ground water rule source water tap? Where can I find Monthly Operating Report (MOR) forms?

Water Sampling Instructions

Additional Resources