A water pressure regulator includes a sealing member and a body having a diaphragm assembly. The diaphragm assembly is positioned and secured within the body to define first and second chambers. The diaphragm assembly has a force acting thereon from within the second chamber. The first chamber defines first and second zones and a passageway therebetween. An inlet of the body is configured to provide water to the first zone and an outlet of the body is configured to deliver water out of the second zone. The sealing member is positioned within the first zone. The sealing member seals the passageway by a force of the water in the first zone acting upon the sealing member and by a gravitational force acting upon the sealing member. The sealing member is formed in the shape of a spherical ball. The water pressure regulator may be used in a watering system.