A method for use in warning about wet flooring conditions is disclosed. The method comprises the use of an indicator composition containing from about 90 to about 50 wt. % of basic compound; and from about 10 to about 50 wt. % of a compound selected from the group consisting of a phthalic anhydride derivative of the formula ##STR1## and a poly-nitrophenolic compound of the formula ##STR2## wherein n is an integer selected from 0 to 4, each Y and each Z is selected from an alkyl group having 1 to 6 carbon atoms and hydrogen, B is selected from hydrogen and --NO.sub.2, and X is selected from ##STR3## whereby an intensely colored solution is formed when the composition is in the presence of an amphoprotic liquid.