The federal Safe Drinking Water Act governs the quality and testing of all public drinking water supplied by water systems in the United States. The EPA works with states, localities and water suppliers to implement drinking water regulations.
Drinking water supplied by public water systems (PWS) in Delaware is regulated by the DHSS Division of Public Health to ensure compliance with the National Primary Drinking Water Regulations.
The National Primary Drinking Water Regulations are legally enforceable standards and treatment techniques that include maximum contaminant levels (MCLs) for regulated contaminants.
Researchers continued to develop new and more effective methods to understand the possible health effects of PFAS. In April 2024, the EPA adopted Maximum Contaminant Levels (MCLs) for five PFAS compounds in Public Drinking Water Systems (PWS):
A Hazard Index (HI) of 1 has also been established for any sample containing a mixture of two or more of the PFAS compounds PFNA, PFHxS, HFPO-DA and PFBS (perfluorobutane sulfonic acid).
As of April 2024, the EPA has finalized Maximum Contaminant Levels (MCLs) in regulated Drinking Water for several PFAS. The details and timeframe are included in the Delaware PFAS Action Plan from the DHSS Office of Drinking Water.
Community water systems are required to report PFAS monitoring results in their annual Consumer Confidence Reports (CCR), beginning with the 2027 report.
Public drinking water systems must also start notifying the public of any PFAS monitoring or testing exceeding values.
Starting in 2029, public drinking water systems will have to comply with all MCLs and notify the public of all PFAS MCL violations.
Learn more on the EPA website.
Water systems that need assistance implementing the PFAS maximum contaminant levels can find information on options and potential financial assistance from the Department of Health and Social Services, Delaware Drinking Water State Revolving Fund (DWSRF).
Learn more about how to apply for DWSRF funds.
DNREC and partners conducted statewide groundwater sampling groundwater through existing public potable wells based on a sampling plan that details the dynamic sampling approach and protocols used to conduct the survey.
The result of that sampling is a Persistent Pollutants Sampling Report that details the actions taken, significant detections and overall distribution of select PFAS compounds across Delaware.
Delawareans who do not have public drinking water generally get their water from private wells. Groundwater (water stored in aquifers below the surface of the earth), directly supplies all private wells. The Safe Drinking Water Act does not apply to drinking water from private wells.
Currently, when PFAS are detected in private drinking water in Delaware at concentrations above the EPA’s PWS established Maximum Contaminant Level (4 parts per trillion), DNREC and DHSS implement a response plan, which may include monitoring and studies to determine alternate sources of water and/or water treatment, to ensure that water supplies are safe to consume. These values have been used by DNREC and DHSS since the values were proposed by EPA in March 2023.
If you own a private well, the EPA recommends learning more about how to protect and maintain your well for all contaminants of concern.
Learn more about private wells, ground water and drinking water from the EPA.
Find information about private well classes and other water well owner resources.
Sampling for PFAS is best done by a professional. DNREC recommends using environmental consulting firms certified to perform work in Delaware under the Hazardous Substance Cleanup Act (HSCA), as well as DNREC-approved laboratories.
Laboratory analysis for PFOS and PFOA by EPA Drinking Water Method 537 may cost $400 or more. This does not include the cost of collecting the sample by the environmental consulting firm.
Water contaminated with PFAS can be treated with carbon filters and reverse osmosis. The American National Standards Institute (ANSI) publishes standards (NSF/ANSI 53 and 58) related to the removal of PFAS through these systems.
The National Sanitation Foundation lists products it has certified to reduce PFOA/PFOS in drinking water.
Related Topics: drinking water, EPA, GenX, PFAS, PFOA, waste and hazardous substances, watar, water, wells
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