Holding tank area uses after removal?

Sep 8, 2020
NerwPort 27 Lakeshore Marina
I am 99% set on installing a composting toilet in my Newport 27. The original flush unit was removed, and a very cheap portable unit installed by a previous owner. Upon my purchase of the boat, the portable unit was literally falling apart, so it is also gone.

The plumbing for the flush toilet and holding tank still exists. However, what to do with it? So far, I am not sure about the condition of the sink/shower plumbing or where it goes (bilge or holding tank), so that may be one use - convert to grey water.

A second thought is to remove the old black water holding tank and replace with a fresh water tank to increase capacity on board. I would be nice to have increased capacity for dish and shower/body washing functions, for extended trips away from a dock.

Any thoughts on this would be quite helpful. Thanks for your time.
Mar 29, 2017
Hunter 30t 9805 littlecreek
Small boat you don't need that much water remove and just use space for towels
Jul 7, 2004
Hunter 30T Cheney, KS
"sink/shower " should go overboard, not stored. My sink drains exit thru hulls . Shower drain gets pumped out the side too.
If your holding tank is mounted like mine, the area isn't easily accessible. Water tank or batteries might work. General storage, not so much.
Jan 7, 2011
Oday 322 East Chicago, IN
The holding tank (19 gallons) on my O’Day 322 is tucked under the rear berth, and is pretty shallow (and right next to the engine bilge).

No good way to use the space...except maybe as @Justin_NSA suggested...battery location maybe.

But for me, I prefer a flushing head and holding tank...go get a nice Raritan manual flush toilet...



May 2, 2014
Hunter 30 St.Petersburg, Fl
I vote for the portapotty or composting toilet, holding tank and hoses are a pain, not really nessesary if only daysailing with short (one week) trips from time to time.