Installing a water hydrant in your yard is a great way to add a handy water source where you need it. The beauty of a frost-proof water hydrant is that it drains itself every time you shut off the water, preventing water from freezing inside the faucet in winter. To ensure the frost-proof function works, the drain valve at the bottom of the hydrant’s standpipe must be buried below the frost line, the depth to which the ground freezes in winter. This varies by climate, so check with your local building department for the recommended depth in your area.
Installing a water hydrant is easiest if you can tap into an existing underground water supply line, such as the mainline for a sprinkler system. If a water supply is not available, you must run a new line to the water hydrant location. In the project shown here, the hydrant is being installed into a PVC water line near some in-ground sprinkler valves, where it is easy to cut into the supply pipe and add a tee fitting for the new hydrant.
Source: The Spruce