Stable aqueous compositions of silane quaternary ammonium compounds are provided by diluting an alkanol solution of the silane quaternary ammonium compound in water with at least one nonionic surfactant. The weight ratio of the silane quaternary ammonium compound and nonionic surfactant is provided to yield a composition which can remain stable in dilute aqueous compositions, can be applied to any surface and dry quickly to provide an anti-microbial film. The addition of an alkali metal bicarbonate salt to the composition improves the anti-microbial properties as well as the drying time of the composition.