Hi All,

I'm building a rather large drip irrigation system using two hose bibs attached to our house. Each hose bib will have a three port timer attached to control six zones in total (each watered at a different time). I understand that the components downstream of the timer are not rated or meant to be under constant pressure, such as the backflow preventer, filter, and pressure regulator, that's fine. Obviously the timer does need to have constant pressure on the inlet side to work automatically.

We're needing to repair or replace one of the hose bibs as it's leaking while on, and in my research on that matter, I was amazed to see that a quality replacement hose bib, such as an Arrowhead (Model 470) or Woodford (Model 14), are also not rated for constant pressure - as would be the case when connected to a timer. This seems completely against the whole purpose of a timer, which is to automate the watering system. I can't believe that the tens or hundreds of thousands of people using a water timer are turning the faucet on before each timed watering session, and back off afterwards. Nor do I believe that all these people are having a plumber add a dedicated line just to their $30 timer so that it's not going through the hose bib. But it would have to go through SOME type of valve, otherwise you'd never be able to replace the timer without shutting off the main water.

So what's the deal? Are the faucet manufacturers just covering their butt in case you leave the hose connected, water on, and you get a freeze? I would only be operating this system over the frost free months, say May through September.