If you are already fluent on how the toilet system works on a boat you can skip this part, otherwise, plug your nose and keep reading. 😊 In a normal home, when you flush the toilet, it goes down a pipe and into the local sewer system where it largely becomes someone else’s problem. In a boat, that problem remains yours as everything that goes down your toilet is ground up in a poop garbage disposal and then pumped into a tank. This lovely cocktail is officially known as ‘black water.’ In our boat, the black water is stowed in one of two 20-gallon aluminum tanks.

For those of you doing the math at home, a total of 40 gallons of black water storage is roughly equal to 60 flushes of the toilet. With 6 people on board, this MIGHT be two days’ worth of flushes. Once the tank is full (or heaven forbid, overflows, which has happened), we must find a marina that will pump out our tanks. Getting the tanks pumped isn’t that bad, but it does require us to find a marina every other day, which is something we’d rather not do. This left us with one of two options. The first would be to add extra black water storage. We have room for and are in the process of installing an extra 20 gallons of black water storage. At best this would buy us one extra day without a marina, so not much of a solution.

The second option, which we did 2x, was to install composting toilets. If you want to understand how a composting toilet works, visit www.NaturesHead.com. With our crew of three adults and three kids, we have to empty the fluids tank every other day and the solid tank every third week, both of which we can do without a marina, thus saving us lots of time and thousands of dollars of marina fees. More on this later.

Calvin helping pull the vent line through the boat bilge

THE INSTALL – The first step in installing composting toilets was removing our existing Jabsco flushing toilet. Proving that I spend far to much time behind a desk, I didn’t think the first one out very well as demonstrated by the following clip. WARNING: This video contains bad words and ‘black water’ everywhere. After this delightful experience, I decided to flush it out the lines extensively before removing the second toilet. This made the process much less painful. Other than the disgusting mess on the first toilet, the removal was pretty easy, simply requiring unbolting the toilets, cutting a few wires and capping a few hoses. With only very small modifications on one toilet (shortening the vent with a saw), the new toilets went in easily. The hardest part was running the required vent hose, which we tied into the vent for the black water tank (see pictures).

OPPERATIONS: All of us were very apprehensive about using the composting toilets as they do require some…. adjustments. To prevent messes and to insure all the liquids go down the correct hole, all boys/men are required to sit. This really wasn’t a big deal for me because (at the cost of losing my ‘man card’) I sit anytime there isn’t a urinal because I hate the mess peeing standing up makes in the bathroom. For the ladies, and I can only share what I’ve been told, ‘aiming’ the liquids to the front of the toilet requires careful positioning. I’m also told that it requires some practice for ladies to not pee while pooping. Again, I’m only the messenger here.

When it comes to #2, it’s the same for everyone. Once you are ready to make your ‘deposit’ you push down a lever that opens what we call the bomb door, where only solids are allowed. This requires some focus as you want your deposit to fall cleanly down the hole, otherwise you will have the very unpleasant task of wiping off the marks. Surprisingly the toilet has almost zero odor when using. Thanks to a small vent fan on the toilet, even with the bomb door open, essentially all smell is pulled out. After every use, you quickly mist the toilet with a vinegar spray, which isn’t the nicest smell, but it eliminates any urine smell. After each deposit of solids, the user must turn a crank handle several times to mix the goods together to assist in composting. I think our biggest operational complaint is that the toilet is

Notice how the toilet is almost to Calvin’s waste.

very high off the ground, leaving everyone’s feet dangling while using the toilet. At 6’2”, I can’t even sit flat footed on the toilet. This is a bit of an inconvenience, but one that is easily solved with a small step stool. While I suppose Natures Head could make a shorter version, this would reduce storage space, which isn’t ideal.

BUT WHAT ABOUT EMPTYING!?! As mentioned above, with a crew of six, the two, 2.4 gallon liquid containers have to be emptied every other day. I’m not going to lie, this is NOT a pleasant task, but it’s not horrible either. Thanks to a cup of vinegar added to the containers after they are emptied, the smell of urine is mild, but still present. As soon as you remove the container you quickly install a cap to prevent spills (Heaven Help Us!) and to trap the odor. Most composting toilet users simply dump this overboard, which they claim isn’t any different than the common practice of peeing off the back of the boat. Depending on where we are, we too might be guilty of this practice, otherwise we dump the liquids into our waste tank for future pump out.

BUT WHAT ABOUT THE $#!^%??? We’ve only had to do this once so far and we were TERRIFIED! Nature’s Head recommends waiting at least 6 hours after the last deposit before emptying the solids to help prevent odors. To be safe, we waited an entire 24 hours. Fully expecting to vomit from the smell, we all held our breath and pulled apart the toilet to remove the solids. To our massive surprise, there was ZERO foul odors. Seriously! No bad smells, at all. It just smelled like really rich gardening soil. Not compost and certainly not poop. Just dirt. A kitchen sized garbage bag fit over the container, which we flipped over to shake out the materials. Anything that didn’t shake out is simply left in the container to continue composting. Before reassembling we added two gallons of coconut husks which help with composting.  Really not bad at all. What’s that? Where did we take the bag of composted human waste? Well, this is a murky area of composting toilets. On land you can simply bury it in the ground as fertilizer. Most mobile com-posters simply double bag it and drop it off in a dumpster. This isn’t always legal, so let’s move on.

FINAL THOUGHTS: I highly recommend a composting toilet. Only a major tree-hugging hippie would put one of these in their house, but for a boat or RV, it’s a great solution to a crappy problem (sorry, couldn’t resist).

“Liquids” bucket. SOMEBODY didn’t notice it was already full!

Location (pre-cleaning) for new toilet