I know this article is about the fresh water system but I need to make a plug for the sanitation system.


This owner did a DIY winterizing and paid a really huge price. The price for improperly winterizing the holding tank was massively repulsive odors in the boat! Come spring when the frozen shit & urine melted the leaks began, this was only one of them. The entire boat wreaked of raw sewage! He went in late and the leak was not discovered until early June. Under the hot cover the odors had baked into everything. He had flushed one gallon of -50F PG through the head. His hoses held more than one gallon and the tank still had at least 3-4 gallons in it!


This is also another reason I do not like elcheapo PVC sanitation hose. Every leak from freezing was in the white PVC hose... Rubber based hoses may have survived this, PVC did not.


#1 Holding tanks should be COMPLETELY empty BEFORE you winterize them.


#2 Hoses from head to tank should be purged of effluent by dry pumping.


#3 Try to wash out your tank before putting the boat away. Most tanks have a clean out port, use it.


#4 Ask your pump out guy to do a flush service. Evacuate, fill with clean water, re-evacuate.


#5 You may need a manual pump to get the tank dry. Pump into a 5 gallon bucket and pour it into a land based toilet.