Perfluoroalkyl substances (PFAS) have been used extensively in manufacturing stain resistant and water repellent consumer products and in firefighting foams at airports and military sites. These substances have been released into the environment inadvertently and when sprayed during firefighting scenarios and simulations. Due to their slow environmental degradation they have contaminated water supplies in multiple counties in the US, potentially exposing more than 5 million people nationwide. The community water supply in Paulsboro, NJ was contaminated with a PFAS – Perfluorononanoic Acid (PFNA). Since 2014, the water supplies have been filtered with activated charcoal. To assess the effectiveness of this water intervention program on reducing exposure to PFAS, a convenience sample of 120 adult residents in the area have been recruited and PFAS were measured in serum, household tap water and household dust; a questionnaire was administered as part of a CDC Biomonitoring grant. Three visits were planned to take place approximately a year apart: the first visits have been completed and the second visits are in progress. The blood test data showed that the serum PFNA levels of the residents often exceeded the 95th% reported in the 2009-2010 NHANES levels for adults over 20. Computational simulations were conducted for all the subjects, employing an integrated exposure and physiologically-based pharmacokinetic (PBPK) modeling approach, using inputs derived from questionnaire information provided by the participants. The results of these simulations also show elevated PFNA serum levels, consistent with available blood test data. Current water levels were below detection for all PFAS, indicating that the water intervention has effectively reduced PFAS exposure through that route, while PFAS were found in dust, reflecting their use in consumer products. It is expected that the serum levels of PFNA will be declining over the next few years if the drinking water was the main exposure source.