Winterize sanitation and fresh water systems.
You don't need water for that...you need to get rid of what's on board. Here are the instructions for winterizing your plumbing: Fresh water system1. Drain the water tanks completely (just turn on all the faucets).2. Drain water heater. Most have a drain petcock; follow manufacturer’s instructions to find it and use it. Remove both the inlet and outlet hoses, and if necessary use a shop vac to be sure of gettting all the water out of it.3.Connect water heater inlet and outlet hoses together. Bypass kits for this purpose are available from boat stores and RV supply stores. 4. Add non-toxic antifreeze ("the pink stuff") and pump that through the system until all outlets--hot and cold in the galley, head, shower, and any deck wash--run only antifreeze. Leave all the faucets open to make sure there is no pressure in the system. Sanitation system1. Pump holding tank out, then rinse thoroughly by completely filling with fresh water and 1 gallon of white vinegar twice.2. Close toilet intake through-hull, disconnect inlet hose and stick it in a gallon of non-toxic ("the pink stuff") antifreeze. Pump the whole gallon through the system into the holding tank. Do not reconnect head intake hose to the through-hull.3. Pump the head 50 times to get as much fluid out of the system as possible.4. After the boat comes out of the water, open all the sea cocks to drain any trapped water.Do not use antifreeze in a Lectra/San or PuraSan. Follow manufacturers instructions to winterize all Type I and II MSDs.