Vic's found one of her sprinklers is leaking underground, so she's dug a great big hole around it. As it's on a 90 degree bend, and we didn't want to pull everything apart to replace it, we installed a flexible hose. It didn't pass any water. We played around with it for a while, to make sure it wasn't blocked or anything, then gave up and dug up the rest of the hose. That wasn't blocked either. Eventually we figured out that the flexible hose, inside the protective sheath, was twisted by screwing it in - I haven't see that before, and we have a bunch of these installed. Anyway, we untwisted it, and the water, it flows.