A pressure regulator for a drinking system for birds or other animals that includes a housing and first and second engaging members for engaging the elongated supports for the fluid supply conduit of the drinking system. The first engaging member includes a pair of ends, each end including a plurality of flexible fingers extending generally parallel to the fluid supply conduit. The second engaging members are adapted to engage the flanges of the elongated supports. The pressure regulator includes a valve element and the housing desirably defines a valve bore for receiving the valve element. The valve element desirably includes a circular seal having a peripheral edge that extends radially inwardly and that includes a lip for sealing the valve bore when the valve element is in the closed position. Desirably, the housing includes a central portion that defines a central channel having a larger diameter than a fluid inlet channel defined by the housing, and an air exhaust port associated with the central portion for exhausting air trapped within the central portion. The housing also desirably is configured to facilitate quick and easy removal and replacement of the seal. The pressure regulator may be used in connection with poultry houses having sloped floors.