Are Marine Composting Toilets Different?
Many people wonder if there's a difference between standard composting toilets and marine composting toilets. The answer is complicated, is it depends on the brand and the boat. Many standard composting toilets, which are designed for houses, work perfectly fine on sailboat applications, while others definitely do not.
All of the models on this list can be used on boats, though some require varying levels of modification to be sanitary and to work properly. Positive ventilation is almost always required for a functioning composting toilet, and this can usually be accomplished with a simple low-volume DC fan and a pipe.
Composting Toilet Legality
But what about the Coast Guard? Are there different rules for both with composting toilets? Yes, but in many cases having a composting toilet is actually easier. The Coast Guard's primary concern with toilets is where the waste goes. As long as it doesn't end up in the water where it's not supposed to, then it usually isn't a problem.
That means no dumping or pumping in areas where you're usually not allowed to empty a septic tank. The rules refer to toilets as Marine Sanitation Devices or MSDs. There are different types of MSDS that are subject to different requirements.
According to the EPA, composting toilets are usually considered Type III MSDs, which do not have to be certified by the Coast Guard. They can therefore be used anywhere a Type III MSD can be used as long as they're installed properly and don't discharge waste in unapproved locations.
Requirements vary between boats based on size. Be sure to check Coast Guard, state, and local requirements for your specific boat size and configuration before installing a different toilet.
Choosing the Best Sailboat Composting Toilet
Composting toilets are still fairly new arrivals to the market, so it can be difficult to figure out which one to choose. There are not a whole lot of composting toilets that can be used on boats, given the nature of composting waste in an enclosed environment. That said, there are a few qualifications that make composting toilets ideal for marine use.
First, a marine composting toilet should be entirely self-contained and sanitary. This is especially important in a small enclosed environment like a sailboat head. Additionally, all areas that contain liquid should be leak-proof, and the ventilation pipe should be adaptable for use on a boat.
Given that marine toilets are subject to rolling, they should have sufficient space in the holding tanks to prevent waste from splashing back up the toilet during heeling or rough weather. They should also be compact enough to fit well in a sailboat head.
Best 5 Composting Toilets for Sailboats
We scoured the internet and found five of the best composting toilets for use in sailboats. These toilets come in multiple shapes and sizes, and there's one available for almost every vessel size and configuration.
Though most of these toilets are not specifically designed for marine use, their characteristics make them suitable for adaptation (though some modification may be required).
1. Air Head Mobile Composting Toilet
The Air Head composting toilet is the go-to model for sailboats and powerboats. It's been featured and reviewed and famous publications such as Cruising World, Bluewater Sailing, and Practical Sailor, and it's a favorite of boat builders in many areas.
The simple and self-contained system does away with complex pipes and sanitation tanks without causing unpleasant smells or unsafe conditions. The toilet itself is quite compact, though it hardly resembles typical marine toilets. It features separate holding tanks for liquid and solid waste, which keeps everything efficient and sanitary.
When you purchase the toilet, you purchase your boat's entire sanitation system (more or less), and it's extremely easy to install. All you have to do is hook up the ventilation hose properly, and you'll have a composting head with everything you need to get started.
The airhead composting toilet is one of the most compact units on the market, and it still features all of the typical components found on proper composting toilets. It's safe to use in a rolling and pitching environment, as its self-contained holding tanks are designed to resist leakage.
Overall, the Air Head mobile composting toilet is the best option for sailboats, especially if you're removing an existing head. It's affordable and designed specifically for mobile applications. It's made in the USA with the highest quality materials and most reliable parts.
2. Nature's Head Self Contained Composting Toilet
The Nature's Head self-contained composting toilet is a proven and time-tested product that made a name for itself in tiny houses and off-grid cabins over the years. Its basic design principles are quite similar to the Air Head mobile composting toilet, as this configuration has proven to be quite reliable and pleasant for users.
It's larger than the Air Head composting toilet, but it's still compact enough to fit in most sailboat bathrooms. This model has also seen fairly extensive use on sailboats, even though it's not specifically designed for marine applications.
The chambers are separated, sealed, and lashed together with heavy-duty metal latches. This makes them quite impervious to the rolling and pitching that you're likely to encounter in the cabin of a sailboat. Additionally, the Nature's Head self-contained composting toilet is simple to operate and long-lasting.
Operation is simple, and this composting toilet's holding tanks have a very large capacity. According to the manufacturer, the toilet can be used full-time by two people and emptied only every 4 to 6 weeks. This is great for liveaboards if they don't have to worry about emptying their storage tanks in a place where they're not allowed to.
The design of the Nature's Head composting toilet is modern, which is why it can be so compact and yet highly sanitary. It weighs a mere 28 pounds empty, which means that it will not throw off the balance of your boat when installed.
3. Separett Villa 9215 Composting Toilet
The Separett Villa 9215 composting toilet isn't what you'd traditionally consider a marine toilet, but its design is robust and simple enough to adapt to marine applications. It's a self-contained unit with positive ventilation and separate sealed tanks, which makes it a good candidate for marine use.
It operates on AC or DC power, which is convenient for vessels that are typically wired for 12-volt direct current. Since the unit is entirely self-contained and features a separate gray water tank, it should qualify as a Type III Marine Sanitation Device (MSD).
Solid waste is contained inside of a disposable liner bag, which makes it sanitary and convenient for offloading periodically at the dock. If you have a little more space to work with, the Separett Villa 9215 composting toilet is a good option that's worth considering.
4. Sun-Mar Compact Electric Self-Contained Composting Toilet
The Sun-Mar composting toilet is a self-contained and sanitary unit that makes an excellent option for a boat with a larger head. Though the toilet isn't designed specifically for marine use, Sun-Mar toilets are well-known for use in moving tiny homes and other non-stationary applications.
The Sun-Mar composting toilet is quite advanced, as it includes a thermostatically controlled heater to produce the best quality compost. Additionally, it features electric fans for ventilation that draw minimal power.
The unit is relatively lightweight and entirely self-contained. It's larger than some of the other models on this list, though it's an excellent representation of industry-standard composting toilets. The unit requires a 2" ventilating stack, which is common and usually made of a lightweight and easy to work with material such as PVC or ABS.
5. Pikkuvihrea Waterless Composting Dry Toilet
The Pikkuvihrea waterless composting toilet is the simplest model on our list. It can be adapted for marine applications, though it's probably best suited for houseboats or liveaboard sailboats. The model is entirely self-contained and features very few separate parts.
Unlike most composting toilets, this model comes with virtually everything you need to install and use the toilet. This includes all the necessary hoses, vent pipes, and inserts. The model doesn't have a separate sealed container for liquids, which could be a downside on sailboats (especially in rough water).
Overall, the Pikkuvihrea waterless composting toilet is an affordable and simple composting toilet that will get the job done. If you need a toilet in an extra compartment, or if you're shopping on a budget, the Pikkuvihrea composting toilet should meet the mark. It's lightweight and easy to use and requires no water or drain plumbing.
