PROBLEM TO BE SOLVED: To provide a drainage facility capable of easily and sustainably preventing harmful organisms living in water such as wrigglers, without possibility of causing environmental pollution.SOLUTION: A drainage facility is provided with at least one pest control agent having a particle diameter of 1 mm or larger which is selected from the group consisting of soluble glass which allows silver ions to be eluted in water and resin moldings formed of resin with a standard moisture regain of 1 to 10 containing a silver-substituted inorganic ion exchanger, and a water storage-drainage member. Preferably the pest control agent has an amount of silver elution in water of 0.05 mg/(g L day) to 5 mg/(g L day).【課題】 ボウフラなどの水中に生息する有害生物の防除を、簡便に、持続的で環境汚染の恐れなく可能にした貯排水設備を提供する。【解決手段】 銀イオンを水に溶出させることのできる溶解性ガラス、および公定水分率が１～１０である樹脂に銀置換無機イオン交換体を含有させた樹脂成形体、の中から選択され、粒径が１ｍｍ以上である1種以上の有害生物防除剤および貯排水部材を備えた貯排水設備。有害生物防除剤は、水中への銀溶出量が０．０５ｍｇ／ｇ・Ｌ・日以上、５ｍｇ／ｇ・Ｌ・日以下であるものが好ましい。【選択図】 図１
