Emerging Contaminant Update Presentation to NH Septic Installers

January 25, 2019



Five Takeaways on Emerging Contaminant Update Presentation to NH Septic Installers

In December, GeoInsights director of water supply, Dave Maclean, provided an update on emerging contaminant issues to the  New Hampshire for Septic System Designers and Installers Association organized by the New Hampshire Water Works Association(NHWWA). This program is provided roughly every two years to provide septic system installers with updates on technologies and regulations relating to on-site waste water discharge and design.  Here are five top takeaways from his presentation:

  1. PFAS in Drinking Water-  In January 2019, the New Hampshire Department of Environmental Services (NHDES)  will be initiating rule making on establishment of maximum contaminant levels (MCLs) in drinking water for four per & poly fluorinated alkyl substances (PFAS). MCLs must consider health benefits as well as costs to water systems for treatment. The topic of PFAS toxicology is rapidly evolving and NHDES recently hired a toxicologist and risk assessor to assist with these efforts.  Click here to see a list of reference documents being considered by NHDES

  2. PUCMR 4 and Water Testing for New Emerging Contaminants- The PFAS concerns grappled with cross the New England and across the nation were triggered by drinking water system sampling for emerging contaminants required as part of the third round Unregulated Contaminant Monitoring Rule (UCMR 3) which is part of the 1996 amendments to the Safe Drinking Water Act. Testing for the fourth round, (UCMR 4) will be ongoing from 2018 to 2020 and water systems will be required to sample for a variety of new contaminants including 10 cyanotoxins, 9 haloacetic acids (disinfection byproducts), 2 metals (germanium and manganese), 9 pesticides, and 3 alcohols found in cosmetics, flavorings and personal care products.Click here for the United States Environmental Protection Agency's (USEPA) summary of UCMR 4.

  3. Manganese -  One of the UCMR 4 contaminants, manganese, is a common component in New Hampshire groundwater, with recent health studies linking manganese to learning disabilities.See this article by the International Journal of Environmental Research and Public Health. Manganese currently has an Ambient Groundwater Quality Standards (AGQS) of 840 ug/L and a secondary standard of 50 ug/L.

  4. Arsenic- Also in January 2019, the NHDES will reevaluating the AGQS for arsenic. The current arsenic AGQS is 10 ug/L and initial 2018 legislative bills recommended AGQS concentration as low as 0.004 ug/L based on estimated cancer risks and health risks. DES estimated that level that low could cost water suppliers between $2 million and $3 million per year for treatment;click here for a copy of the final law

  5. 1,4 Dioxane- In September 2018, NHDES updated the AGQS for the state, one drastic change was the reduction the AGQS for 1,4 dioxane to 0.32 ug/L. At these low levels, approximately half of the groundwater discharge permit sites in New Hampshire were discharging waste water which exceeded these levels. NHDES released rules in September to accompany the AGQS reduction to allow discharge of up to 2 ug/L of 1,4-dioxane if certain provisions were made, which we anticipate will lead to many site closures.See New Hampshire Code of Administrative Rules, Env-Wq 402.24 found here


Download the full presentation here:



Questions about Emerging Contaminants or Water Supply Standards in New Hampshire?


Contact Dave Maclean


Dave Maclean, PG, LSP, LEP| Director of Water Supply

damaclean@geoinc.com| 603.314.0820

Dave has broad experience in water supply and contaminant hydrogeology projects throughout New England.