Just right this year, I try and extend it as long as I can, and experience has shown I can do so until we get several nights in a row with low teens temps, near single digits. One year I pushed it a bit too far...., and it froze up and broke the cast aluminum housing that holds the Pelton wheel, never again! All I do is pull the intake tube that goes from the creek culvert that goes under the road to my screened collection box a few feet below, at the top of my property, then i go to the bottom where the turbine is, 147' vert below, and disconnect the line there. Then it auto drains out, simple, and only takes maybe 10 minutes, about the same to boot it up in the spring. It's not even close to being worthwhile to freeze proof it, all the excavation required, near a water way, would be a nightmare of permits etc. Plus it's super rocky. Solar remains the simplest and most idiot proof of renewable energy, put it up and forgetaboutit. But I sure like the 24/7 aspect of the hydro, for the 9 months out of the year it's operating.