PATIO IRRIGATION MOUTH WITH DRAINAGE LIGHT RETENTION VALVE DESCRIPTION OF THE INVENTION This invention is directed towards a patio irrigation duct, and more specifically to a patio irrigation mouth that prevents contaminants and the like from entering the mouth of the patio. patio irrigation. Patio sprinklers are well known in the art and have an inlet valve connected to a water supply that is located below the freezing limit on the ground. When a patio irrigation spout is closed, a drain port on the inlet valve opens to allow water to drain into the spout. The problem with this design is that ground water or other contaminants can enter the patio hydrant through the same drain port, thus creating an unacceptable cross connection. Therefore, there is a need in the art for an improved patio irrigation nozzle. Thus, a main objective of the present invention is to provide a patio irrigation nozzle that prevents backflow through the drain port. An additional goal is to provide a patio watering that is easier and simpler to repair. These and other objectives will be apparent to those with experience in the art. A patio irrigation duct having a valve body coupled to an inlet water pipe, a vertical pipe coupled to a valve body, and an upper casting part coupled to the vertical pipe. The valve body has a valve seat and a drain port. Arranged within the valve body is a valve or piston attached to a valve rod or rod extending vertically through the vertical tube and operatively connected to a lever or spigot handle. The upper casting has an inlet port, an outlet port and a conduit extending from the inlet port to the outlet port. Mounted inside or outside the valve body is a check valve that is placed to prevent the flow of water from the soil or other contaminants from entering the mouth of the yard through the drain port. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a patio irrigation pipe; Figure 1A is an elongated side view of a check valve adjacent to the drain port of a patio irrigation nozzle of Figure 1; Figure 2 is a side view of a patio irrigation nozzle; Figure 2A is an elongated side view of a check valve adjacent to the drain port of a patio irrigation nozzle of Figure 2; Figure 3 is a front view of a patio irrigation pipe with a separate hollow pipe; and Figure 3A is an elongated side view of a check valve in communication with a drain port of a patio irrigation nozzle of Figure 3. A patio irrigation nozzle 10 has a valve body 12, a seat 14 valve, a port or inlet port 16, an inlet 18 which is connected to a pressurized water source (not shown) and an outlet 20 in its upper part. Connected at one end of the valve body 12 is a vertically extending vertical tube 22 and is connected to an upper fused part 24 at the opposite end. The fused part 24 has an inlet 26 coupled to the vertical tube 22 and a discharge or outlet conduit 28 which preferably extends downwardly and externally from the upper fused part 24 and a fluid conduit 30 extending between the inlet 26 and the outlet 28. Arranged within the valve body 12 is a shut-off valve or piston 32 which is connected to a valve rod or drive rod 34 extending from the shut-off valve 32 through the vertical pipe 22 and connected to an actuator device 36 attached to the upper cast part 24 such as a lever or handle. Mounted adjacent to the drain port 16 is a check valve 38 which is positioned to allow fluid to flow from the valve body through the drain port 16 to the ground while preventing fluid from flowing from the ground again towards the mouth 10 of patio irrigation through the drain hole 32. Alternatively, the check valve is in the plunger 32. The check valve 38 is of any type such as a spring-loaded valve as shown in Figure 3 or similar to that described in U.S. Patent No. 5,632,303 incorporated herein by reference. reference in its entirety. The check valve 38 is mounted in any conventional manner such as, by way of example only, within a housing 40 in communication with the drain port 16 as shown in Figures 1 and 1A or mounted within the valve body 12 as shown in Figures 2 and 2A. When the shut-off valve 32 engages the valve seat 14, the hydrant is in a closed position which prevents water from flowing from the water source to the discharge conduit 28. When the shut-off valve 32 is in the closed position, the drain port 16 allows water to drain out of the tube 22 and into the ground. The check valve 38 prevents water from flowing in the opposite direction from the ground to the irrigation nozzle 10 through the drain port 16. When the shut-off valve 32 is disengaged from the valve seat 14, the shut-off valve 32 seals the drain port 16 and allows water to enter the vertical tube 22 and under pressure flow to the discharge conduit 28. In an alternative embodiment, a separate pipe assembly 42 joins the patio irrigation nozzle 10. The tube assembly has an elongated hollow tube 44 that extends vertically in spaced apart relation to the hydrant. The tube 44 preferably has two ports 45 and 46 positioned below the freezing limit. A cover 47 can be placed at the opposite end. The port 46 is in fluid communication with the drain port 16 by means of an integral mold / casting or the like or a connecting member or tube 48. Alternatively, the port
16 is removed and there is a direct connection between the valve body 12 and the port 46. Mounted within the tube 44 and adjacent to the port 46 is a valve
38 which is positioned to allow water to flow from the irrigation port 10, through the drain port 16, to the connection pipe 48 to the pipe 44 and subsequently to the earth through the port 45 while it also prevents water from entering the hydrant from tube 44 or the earth. The check valve 38 can be mounted in any conventional manner. When the check valve 38 is worn or damaged it can be removed from the tube 44 by the use of a tool and can be replaced. Alternatively, the check valve 38 is mounted within a second tube 50 having a diameter smaller than the tube 44. The tube 50 fits within the tube 44 so that the check valve aligns with the port 46 to operate in the same way as previously described. In this way, the check valve 38 can be removed and replaced by removing the second pipe tube 44 or alternatively by a tool such as a bar. A mouth watering yard that reduces the possibility of contamination of the water supply of the groundwater through the drain port has been described. An alternative has also been described that allows for easy repair and replacement of such patio watering. Thus, all the established objectives have been met.