You really should winterize by using the RVAnti-freeze to be shure.  If
you start with a drained H2o tank it won't take so much  and you will
have the peace of mind knowing your pump and faucet are not going to
freeze.  My faucet froze, cracked and was a real hassle to fix.

Ed Lowe
82 Westy diesel
85 Golf diesel
92 Cabriolet