A fluid pressure regulator with a no-drain valve where the no drain valve also serves as a pressure reactive member to operate the pressure regulator valve. At low pressure settings, the no-drain valve is biased closed, and the regulator is biased open. As pressure progressively rises, the no-drain valve opens, then abuts a piston component of the regulator valve, and as pressure continues to rise, moves together with the regulator piston to move the regulator valve toward a closed position, thus regulating pressure.