I haven’t measured it but can’t imagine it’s anything over 100 PSI. That said. I’ve hooked it all up and nothing exploded 
Although v1.2 docs say: tap -> pressure regulator -> hose -> solenoid -> bot
I’ve connected it like: tap -> hose -> solenoid -> pressure regulator -> bot
But here in Australia (and probably everywhere except USA) the pressure regulator has 3/4" Female Hose Thread which does not match the more universal British Standard Pipe thread. Luckily, the distance to thread is short so although you can feel the threads don’t match, by the time friction kicks in you’ve already sealed the connection 
Not sure how long it will last…