The invention provides a stable water treatment agent composition containing a bromine-based oxidizing agent, a sulfamic acid compound and an azole compound, for which the generation of deposits is reduced even under conditions such as outdoor storage where the composition is exposed to irradiation with light such as sunlight. The water treatment agent composition contains a bromine-based oxidizing agent, a sulfamic acid compound, an azole compound, and at least one of a surfactant and an N-vinylpyrrolidone monomer-containing polymer, wherein the surfactant is at least one compound selected from among amphoteric surfactants, anionic surfactants and nonionic surfactants.本發明提供一種水處理劑組成物,含有溴系氧化劑、胺磺酸化合物及唑類化合物,係即使在受到陽光等光照射之室外保存等條件下,亦可減少析出物之生成的穩定的水處理劑組成物。一種水處理劑組成物,包含溴系氧化劑、胺磺酸化合物、唑類化合物、以及界面活性劑及含N-乙烯基吡咯烷酮單體之聚合物中之至少1者,該界面活性劑係選自於兩性界面活性劑、陰離子性界面活性劑、及非離子性界面活性劑中之至少1種。無
