The water filter is Made in USA, and granted a patent in 2001 which possesses an U.S. patent number: 6,197,193.
You may also read more about the technology by visiting the link here: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6,197,193.PN.&OS=PN/6,197,193&RS=PN/6,197,193