I have a yard hydrant installed in my front yard. It is connected directly to the water supply from the city. The yard hydrant has a drain at the bottom that allows water to drain from the hydrant when not in use to prevent freeze damage will this also work to prevent backflow?
Here is the link to the spec sheet. Specifically I have a boshard YHP-02.
The anti-siphon device still doesn't meet the requirements of the UPC as the bacteria from the weep hole is connected to your water source. A backflow is required at the base of the hydrant when connected to city water. Both devices are required if you want to use the hydrant for drinking water.
The catalog and product sheet don't mention backflow, and I assume that's a feature they would want to highlight. The same company also sells backflow prevention devices so its something they know about. You could call and ask, or test it by trying to make it backflow, but let's assume that it doesn't protect against that for the rest of the answer.
A hose mounted backflow preventer is a common accessory and even required in a lot of areas. You can just screw this onto the output of the faucet and then connect a hose to the backflow preventer.
To allow the freeze-protection draining system to work, the backflow preventer may have to be unscrewed. They are usually spring operated, and the could provide enough resistance to hold water in the pipe. They are made to stop water flowing back in, and could get stuck and stop air from entering the pipe allowing water to drain.
