An ultraviolet (UV) water treatment device includes a housing with an inlet and an outlet. Water flows into the housing through the inlet, is exposed to the UV light, and the treated water then flows out of the housing through the outlet. The UV light source is inserted into a quartz tube from above so that the UV lamp can be changed without draining the system. A lower access port is provided in the bottom of the housing. The lower access port includes a seat that contains the lower end of the quartz tube, and further allows a user of the system to remove debris from a broken quartz tube quickly and safely.