Abstract: A cartridge-type valve assembly for controlling the flow of water to a plumbing fixture including a bonnet molded from a plastic material threadedly receiving a stem also formed of a plastic material. The bonnet defines a depending skirt having an inlet for receiving fluid and defining a sealing surface engageable by a sealing element preferably an O-ring, carried by the stem. Noise reducing structure preferably a plurality of flutes are formed in the bonnet, near the inlet and operate to reduce or inhibit noise in the valve as the sealing element moves into engagement with the sealing surface. The flutes open into the inlet and taper as they extend toward the sealing surface, gradually merging and blending into the sealing surface. The O-ring is replaceable thus eliminating the need for replacing the entire valve cartridge should a failure in the sealing element occur.