the present disclosure teaches a practical method and apparatus for providing accurate , economic drinking water testing using materials available worldwide : a mirror 10 , cell - phone 20 , and a plastic bag 30 . cell - phone 20 contains a c # computer application which captures color digital images of water whose water quality is desired , processes said color digital images , and displays information suitable for determining water quality on said cell - phone . the present invention is susceptible to use by the majority of persons capable of cell - phone operation .