Holding tank vs composting head

[fred1diver]

Hello everyone, we are about to pull the trigger on a new holding tank, but I am wondering, should we go back to neew plumbing, tank, having the “fun” of pumping out… or go with a composting head???
What are your experiences with composting vs holding tanks???
Cost wise?
Maintenance…
I need all the info possible before we spend our hard earned money
Thank you all

 

[Project_Mayhem]

What are your biggest complaints about a traditional holding tank setup?

Personally, I prefer pumping out over carrying a container of waste to dispose of on land

 

[JBP-PA]

Do you have an easy, convenient, free way to pump out? I've heard that some places in Canada can be expensive. How much do you use it? I use my head frequently but normally not 24/7. I have to pump out every couple weeks or so and we have several free places to do so on our way in or out to the lake. I think that it would be annoying to have to carry the liquids container somewhere every day. I occasionally also stay out for several days at a time so I'd need multiple liquids containers. In the Great Lakes NDZ it is illegal to dump it overboard, though many do.
If you only use it rarely, a composting or even portable might be more appropriate.

 

[Project_Mayhem]

Are there composting heads with holding tanks for urine?

 

[Alan Gomes]

I use my head frequently but normally not 24/7.

Man, I sure hope not! Otherwise a change in diet is warranted.

 

[jssailem]

Are there composting heads with holding tanks for urine?

Yes. Most of them have a separate container for urine.

Now, what are you to do with the urine? The Great Lakes (and their interconnected waterways) are generally considered areas where no discharge of treated or untreated sewage (urine included) is allowed from vessels.

The regulations say nothing about standing on the side of your boat and peeing in the Great Lakes, but you are not permitted to dump a bucket of pee in the Great Lakes.

 

[Project_Mayhem]

Yes. Most of them have a separate container for urine.

I was think of a holding tank that could be pumped out

The regulations say nothing about standing on the side of your boat and peeing in the Great Lakes, but you are not permitted to dump a bucket of pee in the Great Lakes.

We were doing that on the Chicago river on the way to the yard at the end of the season. There's no pump out and I didn't want it sitting in the tank over the winter

 

[jssailem]

They are far from maintenance-free. They are usable.

5 Best Composting Toilets - Feb. 2026 - Chicago Tribune

Our team of experts has selected the best composting toilets out of hundreds of models. Don't buy a composting toilet before reading these reviews.

reviews.chicagotribune.com

"Composting toilets require more maintenance and care than regular toilets to avoid odors, insects, and other health hazards. In addition, most require a 12-volt battery or 110-volt plug in order to power the ventilation fan that comes with them."​

 

[MFD]

I also always wonder about the boats with composting heads - how they manage the urine without a trip ashore every day or two to dump the bottle(s).

Aside from legal matters, I don’t know enough about biology as to whether pouring urine overboard vs. urine+feces has significantly less impact ecologically.

 

[Project_Mayhem]

I also always wonder about the boats with composting heads - how they manage the urine without a trip ashore every day or two to dump the bottle(s).

Aside from legal matters, I don’t know enough about biology as to whether pouring urine overboard vs. urine+feces has significantly less impact ecologically.

The urine is sterile, or at least was. The fish probably like the solids. Hopefully those dont float when tossed overboard LOL

 

[jssailem]

I wonder what a school of salmon leave behind in the waters they swim.

I know better than to follow the tail end of a couple of whales up here on the Salish Sea.

 

[JBP-PA]

The urine is sterile, or at least was. The fish probably like the solids. Hopefully those dont float when tossed overboard LOL

Urine is not sterile. Popular myth though.

Is Pee Sterile? Here’s What the Science Says

A urologist debunks the claim that urine is sterile, along with other myths you may have heard about the curative potential of pee.

health.clevelandclinic.org

 

[JBP-PA]

I was think of a holding tank that could be pumped out

I suppose you could rig the liquids to divert into a conventional holding tank. It might save carrying spare liquid buckets for extended days at sea.

 

[MikeHoncho]

What are your biggest complaints about a traditional holding tank setup?

Personally, I prefer pumping out over carrying a container of waste to dispose of on land

Man, I don't. I can take a plastic bag and dispose it of it in a garbage can compared to finding a pump out dock. It is a no-brainer.

 

[MikeHoncho]

I've had my composting (really desiccating) toilet for three seasons now. I take my boat on 1-2.5 week-long trips with my wife, and I have gluten and dairy intolerances (read between the lines). I previously had a typical marine head with a 10-gallon holding tank. We typically had to pump out every other day. In the Canadian Islands, there are little to no pump-out facilities, and those that are there would demand a day to utilize. I don't need to expand on the outcome.......When I switched to a desicant toilet, we easily go week before changing out the toilet charge of coconut husk and what we deposited. Before instituting "no toilet paper in the toilet" protocol, this timeframe was about 4 days. The desicant toilet isn't smell-free, but compared to the smell of the original system, it is light-years better. When its time to change it out there is a "moist dirt" smell. I will not go back to the original marine head.

 

[Foswick]

Urine is not sterile. Popular myth though.

Is Pee Sterile? Here’s What the Science Says

A urologist debunks the claim that urine is sterile, along with other myths you may have heard about the curative potential of pee.

health.clevelandclinic.org

Yeah, but the full story is more interesting. We didn't actually know this until about 2012. It was suspected earlier, but not really proven until then. (I think this came out of Loyola.) The way this was tested is actually pretty interesting ... if you're into microbiology and RNA sequencing. It goes to show you how many discoveries are yet to be made that we only showed what microbiomes bacteria are in common urine ... just a few years ago.

As this pertains to urine's safety, that is a more nuanced question. (I'm going way off on a tangent, so feel free to walk away at this point.)

The bacterial load really isn't the issue. The issue is the nitrogen and phosphorus content. These are actually essential to the ecosystem, but only in normal concentrations. (There is a distinction between freshwater and saltwater environments as to how beneficial they are, but at the volumes we are talking about, I think the distinctions are trivial.)

The issue with urine overboard is one of concentration. If you pee overboard - that isn't a problem (unless you fall in). If everyone in a crowded anchorage/marina does - that's a problem (unless everyone falls, then it is funny). If you pee once, directly - not a problem. If you fill a holding tank and empty that into the water - that's a problem.

Any ecosystem is (or should be) adapted to certain local levels of nutrients. If you dump a concentrated quantity of nitrogen and phosphorus, that risks upsetting that balance. If everyone does it in the same area, that ensures a disruption.

The bottom line: Legally, there is no distinction between urine and fecal-contaminated waste. But, ecologically, it is all about concentration. So, if you must do this and don't care about the legality, do it away from other boaters, away from shorelines, in deeper water, and in small quantities.

But, the caveat is that once urine goes into a holding tank, you no longer know what is in it. So, please, never empty your holding tank into the water in defiance of the law. If you do, don't tell me because I will come scuttle your boat.

 

[Project_Mayhem]

Man, I don't. I can take a plastic bag and dispose it of it in a garbage can compared to finding a pump out dock. It is a no-brainer.

I was referring to urine which might leak out of a bag... or a garbage can after you've walked away. Obviously solids would need to be taken to land if doing a hybrid composting setup

 

[MikeHoncho]

The commercially produced desicant toilets have a urine container of around 2 gallons, designed with a cap. Local bathrooms are easy to find (or other means like dumping in bushes) for the urine issue, compared to trying to find an actual pump out for the traditional systems. It's a no-brainer that the desicant toilets offer greater flexibility for disposal. The downside is needing to have the desicant material available. A brick of coconut husk, properly prepared (it does take time), lasts several two-week trips. You can't just break it up and put it in. You have to reconstitute it with water, break it up into a fine powder, and dry it out, then package it.