When installing an in ground sprinkler system you need to be aware that some cities may require a backflow prevention assembly (also referred to as a BPD). Backflow may occur when the water flows in a reverse direction. This is when different pressures exist between two different points within a sprinkler system.
When running the irrigation line directly off the hose bib, then you will most likely need ad BPD (backflow prevention device). It’s always best to check with what your local requirements are when designing and installing your sprinkler system.