Re: Location of water tank breather pipe
I went back thru the OP. Fallard is correct, the fashion in which your tanks are plumbed, a check valve will not work.
I wouldn't extend the vent into the bilge due to cross contamination issues.
It could be like installing a faucet for drinking water in your toilet.
I'm not happy unless I'm complaining about something.
I'm having a very good day!