Understanding Water Testing Results: A Comprehensive Guide

A guide to understanding your water testing results University of Rhode Island Cooperative Extension Water Quality Program Alyson McCann, Water Quality Program Coordinator alyson@uri.edu (401) 874-5398

Topics What do I do now that I ve had my well water tested? Some common terms and definitions found on a testing report Most important things to look for/ concerns Where to find it on each lab s report

Ive had my well water tested, what do I do now? Begin by working through your test results with this presentation Contact Alyson McCann via email or phone to discuss results and treatment options Visit Cooperative Extension s Well Water Quality Program website for more information on: Tip sheets and water quality standards: https://web.uri.edu/safewater/private-well-testing-and- protection/understanding-your-well-test-results/ Treatment: https://web.uri.edu/safewater/private-well-testing-and- protection/treatment/

Common terms and definitions each state certified water testing lab will provide you with a key to help you understand your well water results Result: The level of contaminant found, or ND (not detected) if the level of contaminant is below the reporting limit. Units for the measure are listed under the "Units" column Reporting/ detection limit (RL/DL): The minimum amount of a contaminant that is significant enough to report Recommended maximum: The recommended maximum level of contaminant in drinking water Minimum reportable level (MRL): The minimum amount of a contaminant that can be detected in the water sample based on the testing method used by the lab

Common terms and definitions Maximum contaminant level (MCL): The acceptable level of a contaminant allowed in well water based on health concerns Secondary maximum contaminant level (SMCL): The acceptable level of a contaminant allowed for aesthetic purposes Not detected (ND): The contaminant was not detected in the sample above the minimum reporting limit (concentrations were not significant enough to report) Action Level: The limit at which water testing results indicate that action must be taken to improve water quality

What to look for on your report The presence or absence of bacteria (E. coli and total coliform) The result of testing for a specific substance or chemical compared to the action level or recommended maximum contaminant level (if either is exceeded, further action is likely needed) The presence of any flags, symbols, or special letters, which relay information about a result consult the lab s explanation sheet and key to understanding your results provided with your test results NOTE: Reports often list detection limits or reporting levels, which are not the same as action levels or allowable contaminant levels, which indicate water quality and the necessity for action. You may need to contact the lab or Alyson McCann to obtain action levels for the substances measured in the report

Understanding and Interpreting your water test results may be difficult Do not hesitate to contact the testing lab and Alyson McCann at the University of Rhode Island for assistance. Alyson will ask you to email your results to her so she can take a look and answer your questions. PHONE: (401) 874-5398 Email: alyson@uri.edu

Check the slides below for where to find pertinent information within your report for state-certified labs typically used by Rhode Island private well owners Aquatek BAL Laboratory Microbac Laboratories New England Testing Laboratory RI Analytical RI Department of Health

Aquatek Labs Bacteria Presence or absence indicated with a checkmark Reporting/ detection limits Listed under MRL (Minimum Reportable Level) with the units listed under the Units column to the left Water standards/ allowable contaminant levels Listed under Limits with a P or S abbreviation. P stands for primary limit (meaning the limit used to judge potability) and S stands for secondary limit, which is a limit that is recommended, usually for aesthetic purposes, but is not required N/A Numbers in BOLD text Specialty symbols (*) means that a limit has been exceeded

BAL Laboratory Bacteria Present or Absent listed for bacteria forms under Microbiology Reporting/ detection limits Listed under Reporting Limits with the units listed under the Units column to the left Water standards/ allowable contaminant levels Listed under Limit. Followed by an M means that the limit is the Maximum Contaminant Level (MCL). Followed by a # symbol means that it is the Secondary Maximum Contaminant Level (SMCL). Limit followed by a symbol indicates that the limit is the action level, meaning if the result reaches that limit then there is a need for action to improve the water quality. Results at the action level are preceded by a star symbol (*) A testing result was measured and may be significant but DOES NOT mean that the result is a problem Numbers in BOLD text Specialty symbols (*) means that a limit has been exceeded

Microbac Laboratories Bacteria Present or Absent listed for bacteria forms under Microbiology Reporting/ detection limits Listed Under the RL column with units for the limits listed under the Units column to the right Water standards/ allowable contaminant levels Listed under Limits followed by either MCL to indicate a Maximum Contaminant Level or SMCL to indicate a Secondary Maximum Contaminant Level Numbers in BOLD text The result has exceeded a limit Specialty symbols N/A

New England Testing Laboratory Bacteria Present or Absent listed for bacteria forms under Category: Microbiology Reporting/ detection limits Listed under Detection Limit with units for the limits listed under the Units column to the left Water standards/ allowable contaminant levels Listed under Recommended Maximum column with units under the Units column to the left Numbers in BOLD text The result is not within the recommended range Specialty symbols N/A

RI Analytical Bacteria Present or Absent listed for bacteria forms under Microbiological (MCL*) Reporting/ detection limits Listed under Det. Limit with units for the limits listed under the Units column to the right Water standards/ allowable contaminant levels Listed after the results in a chart titled Primary Drinking Water Regulations. The chart is separated into different sections with Maximum Contaminant Levels (MCL) listed for different categories of drinking water contaminants. Units for these MCLs are listed in the title for each section of the chart. A separate chart titled Secondary Drinking Water Guidelines is below this section and lists the Secondary Maximum Contaminant Levels (SMCL) N/A Numbers in BOLD text Specialty symbols N/A

RI Department of Health Bacteria Present or Absent will be listed in regards to Total Coliform and E. coli tests under Result Reporting/ detection limits Listed under Reporting Limits with the units listed under the Units column to the left Water standards/ allowable contaminant levels Listed separately from results page (contact Alyson for more information) Numbers in BOLD text A testing result was measured and may be significant, but this DOES NOT mean that the result is a problem Specialty symbols N/A