A water treating device includes a cylindrical housing having a longitudinal axis, an inlet and an outlet. Water to be treated enters the inlet, flows through the cylindrical housing and out the outlet. A plurality of elongated UV lamps are disposed in the cylindrical housing. The UV lamps extend generally in the same direction as the longitudinal axis of the cylindrical housing, but are disposed in a non-parallel relationship with the longitudinal axis of the cylindrical housing. Typically one end portion of each of the UV lamps is spaced outwardly from the longitudinal axis of the cylindrical housing. Along the length of each of the UV lamps, the distance between the longitudinal axis of the UV lamps and the longitudinal axis of the cylindrical housing varies.