Take the drain plugs all the way out.

Completely remove the drain plugs — loosening them isn’t enough to keep a wet housing from cracking.

The whole point of those plugs is to let water escape. If you just crack one open, water can sit in the bottom of the housing, blocked by the plug itself or the gunk around the threads. Even a little water left behind will freeze, expand, and crack the pot or the motor housing. And if the plug is at the lowest point, loosening it often won’t create an actual drain path — it just relieves pressure.

Pulling the plugs fully out does two things: it opens a sweat-free escape route for every drop, and it lets air in behind the water so it actually flows instead of hitting a vacuum. Leave the plugs in a plastic bag and zip-tie it to the pump so you don’t lose them. When spring comes, put them back with a little thread seal