PFAS Facts

Per and Polyfluoroalkyl Substances (PFAS) are a group of man-made chemicals that have been used in a variety of products, including firefighting foam, non-stick cookware, food packaging, upholstered furniture, and clothing. They have been manufactured and used in the United States since the 1940s. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been the most extensively produced and studied of these chemicals.

The main health concerns regarding PFOS, PFOA and related PFAS come from studies in laboratory animals which show effects on the liver and immune system, and on fetal development. Studies also suggest a cancer risk (kidney, testicular), especially for PFOA. PFAS can also affect the endocrine and hormonal systems and can disturb blood lipids which may increase risks for vascular and heart disease.  Studies of human populations exposed to elevated levels of PFOS and PFOA generally support the effects seen in animals. These chemicals are removed from the body very slowly so they can build up over time.

There is no federal enforceable standard (Maximum Contaminant Level or MCL) for any chemical in the PFAS family. However, the US Environmental Protection Agency (EPA) issued a Health Advisory in 2016 for PFOS and PFOA of 70 parts per trillion (ppt). This target concentration in a water sample is for the sum of these two compounds. The EPA intended for the advisory level to be protective of all health effects (including cancer) for all potential consumers of the water. Some states have set their own drinking water targets based upon exposure assumptions and uncertainty factors that differ from those used by the EPA.

The First Taxing District Water Department (FTDWD) owns and maintains four reservoirs and five wells. The reservoirs hold approximately a billion gallons of surface water collected from primarily residential areas in Lewisboro, NY, and Ridgefield, Wilton and New Canaan, Connecticut. These four reservoirs supply, on an average year, more than 85% of the water delivered to our customers.  

The FTDWD serves approximately 42,000 individuals primarily in the eastern and northern portions of Norwalk. There are roughly 500 customers in New Canaan, with Wilton and Westport having about 80 customers each.  

The surface water from the reservoirs is supplemented during droughts and times of peak demand by well water from the Norwalk (Kellogg-Deering) Well Field. 

In 2013, the EPA required water utilities to test the treated surface water and treated well water for PFAS. Under the test method available in 2013, the results were non-detect for FTDWD.  With the ever evolving science and increasing knowledge behind PFAS, newer and more refined testing procedures were developed and accepted by the EPA. The Connecticut Department of Public Health (CT DPH) issued a recommendation on September 27, 2018 that water utilities test for PFAS utilizing these new methods with lower detection limits. The FTDWD promptly heeded this recommendation and tested for PFAS at the reservoirs, wells and treated supplies. This testing detected several PFAS compounds.

• The concentrations in the reservoirs and treated surface waters average 5 ppt (as of June 2019) which is well below the health advisory.  
• The water from the five wells is treated and mixed at the well field before being pumped into the distribution system. The concentration of PFAS in the treated well water has varied from 21 ppt to 38 ppt. The blended well field water is then combined with the surface water before being delivered to our customers. For the last 10 years the wells have provided only a small portion of the water produced, and are used primarily during droughts or hot weather when customers consume more water. In the past six months, due to operational changes discussed below, the well water has been only 2% of the total water produced.
• The PFAS concentration at six representative locations within the distribution system (as of June 2019) has ranged from 3 to 13 ppt for the sum of the 5 compounds, well below the 70 ppt health advisory from the CT DPH. Customers receive and consume the water from the distribution system.

Since the first results were received in January of 2019, for samples collected in December 2018, the FTDWD has adopted operational rules to minimize use of the wells and has taken several wells off line. The FTDWD will continue to monitor and sample for PFAS to ensure that the FTDWD can respond quickly if the water quality changes. The goal of the FTDWD is to provide the highest quality water to our customers. 

More information can also be found on these websites:

• Connecticut Department of Public Health
• Centers for Disease Control & Prevention, Agency for Toxic Substances and Disease Registry
• Norwalk Department of Public Health