A water sampler having a tubular body open at both ends and through which extends a connecting rod fixed at one end to a closure for the lower end of the body and carrying an enlargement at its other end for engagement with and disengagement from a latching clasp supported on a closure for the upper end of the body. The latching clasp comprises a pair of segment-shaped plates between which the enlargement is adapted to be retained, each of the plates having an upstanding motion transmitting member operable to move the plates apart and effect release of the enlargement. The clasp plates preferably are biased to move toward one another by two springs which straddle the connecting rod.