Subject: Re: Just Three Months Ago
The whole point would be a “set and forget” system to drain the pool and spray it over the house.

Yep. And I wouldn't necessarily locate the sprayer on the roof. You had darned well have a tile or metal roof if you want any chance at all in a fire storm. No point in trying to wet those. In high winds, it's probably best located on the ground spraying with the wind into the side and eaves of the house.