# Holding tank size



## Joellen (Feb 14, 2013)

We need to replace the holding tank, our boat came with a 12 gallon tank and we are refitting for cruising long term. We can fit a22 gallon in and keep a drawer or loose the drawer and put in a 38 gallon tank but will have to a lot more work to put it in. Does a cruising couple need 38 or will 22 suffice. Feedback anyone


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## Lake Superior Sailor (Aug 23, 2011)

Just because it will fit what are you going to do with the extra payload! (weight).By way way, Welcome!...Dale


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## Atlas (Aug 21, 2012)

If you're at or near a marina, just get your holding tank pumped as and when needed. When passagemaking, it flushes out directly to sea. So why do you need a big(ger) holding tank anyway?


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## celenoglu (Dec 13, 2008)

Turkish regulations request 2 liters per day per person for two days. This might be a good start.


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## PorFin (Sep 10, 2007)

Joellen,

Suitable tank size depends a bit on your cruising plans and your crew's preferences/habits.

I'd recommend you start your analysis from another direction: How often will you have access to pump-out and/or off-shore dump options?

FWIW: We've got a tank that's about the same size as your current one. We lived aboard for a couple of years. We did the Loop, though we did have a few extended stays in several locations (Brunswick, GA; Marathon; Oriental, NC; Holland, MI) -- and the only time the holding tank size became an issue was when we were on the Black Warrior stretch of the Loop above Mobile, AL.


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## Alex W (Nov 1, 2012)

Don't forget that a very large holding tank (like 38 gallons) will also require considerable structure to hold it in place in rough seas (or in the worst possible case, a roll).

A 38 gallon tank will weigh ~400lbs when full.

Personally I'd rather have useful storage than another 18 gallons of crap...


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## killarney_sailor (May 4, 2006)

Where do you plan to cruise? This can have a big impact on holding tank size.


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## svHyLyte (Nov 13, 2008)

You might want to take a look at RMBOA Blackwater Holding Tank Calculator


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## Cruisingdad (Jul 21, 2006)

Our use is 1-3 gallons, per person, per day. I would plan on two gallons, per person, per day as a good average. And as you are cruising, just remember, there is not a pumpout at every stop. And when you find them, they often do not work. And when you find one that works, you better get ready for a nice charge. We got charged $25 for out last pumpout. So if you have to pump out twice a week, at $25/pop (which is very high, but I am making a point), how does that sit for your cruisin budget? Truth be known, most pumpouts are in the 5-10 range, but likely run higher in the keys.

I think for a couple, I would go for the 38 gallons holding tank.

We are fulltime cruisers.

Brian


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## ellenwhite2 (May 27, 2008)

We have a 15 gallon holding tank. With 2 adults aboard, we pump twice per week. I would go bigger......hmm. maybe that was poor choice of words....


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## Cruisingdad (Jul 21, 2006)

ellenwhite2 said:


> We have a 15 gallon holding tank. With 2 adults aboard, we pump twice per week. I would go bigger......hmm. maybe that was poor choice of words....


No, you just need to train Bob to go in Slinkys litter box!!!

Brian

Ps. Coming your way soon...


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## chucklesR (Sep 17, 2007)

It will of course also depend on your head - i.e. an electric head with a macerator that uses either fresh or salt water as part of it's flush can take anywhere from 1.3 quarts to 1 gallon per flush (presumably for 'solid' flush only, but who knows). 

Go big, but be mindful of the structural issues and weight. 400 extra pounds forward or aft can seriously affect the waterline and under body profile of the boat.


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## bigdogandy (Jun 21, 2008)

Consider replacing your entire existing setup with a composting head and never worry about holding tank size or capacity again. You'll also gain storage space where the old tank had been.


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