A cushioned relief valve includes a housing, a piston, a cylinder cover, and a flexible diaphragm. The housing has an inlet, an interior, an outlet channel, and an outlet, the interior being a hollow cylinder in fluid communication with the inlet and the outlet channel, the outlet channel extending from a cylindrical side of the hollow cylinder to the outlet, the outlet opening outside the housing. The piston is located within the hollow cylinder and is slidable between a first position blocking the inlet and the outlet channel, and a second position opening a path for fluid flow between the inlet and the outlet channel. The cylinder cover defines a compressible gas volume in fluid communication with the second end of the hollow cylinder. The flexible diaphragm separates the compressible gas volume of the cylinder cover from the second end of the hollow cylinder.