Glen "Wiley" Wilson wrote:
Not disagreeing at all, but there may be another way. I've done
several deliveries on Grand Banks trawlers modified with extra fresh
water tanks plumbed directly to and only to the heads, with no
pressure other than a bit of gravity. Do you see any problem with
that arrangement?

No problem at all, as long as there's no interface whatever with the
potable water system....no common plumbing including fill or vent.

Being a sailboater, I find the waste of fresh water
apalling, but the main tanks probably hold 300 gallons. Or more.

It's a different world.

It really is. In this era of so many boats that rarely (if ever) leave
the dock, coastal cruisers that can put in for water any time and
watermakers on boats that actually get out of sight of land
occasionally, fresh water conservation isn't nearly the issue it used to
be. And, electric toilets use only about 1/3 of the flush water they
used to...those designed to use pressurized flush water use even less.

--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304