Frequently Asked Questions About Sun-Mar Composting Toilets

Yes. Our toll-free number is 1-888-341-0782. Our sales department can be reached by selecting option 1, and our customer service department can be reached by selecting option 4.

Sun-Mar’s manufacturing warranty is 5 years for the tank, and 3 years for all other components of the toilet.

Accessory parts are not included in this warranty, and they have a 90 day warranty period. For all warranty inquiries, the serial number will be required.

Please click here for an electronic copy of Sun-Mar’s warranty, which can also be found on the back cover of your owner’s manual.

Please note that, as this is a personal hygiene product, once the toilet has been used, there is a no return policy. However, our customer service department would be happy to discuss any questions and offer the best possible solution.

There are several different drum sizes available, with the Centrex 3000 being the largest available. The GTG, Sun-Mar’s urine separating toilet, has an unlimited capacity to fit multiple installations. However, with all units, the amount of waste in the toilet depends on the number of users.

ANSI/NSF Standard 41 is the North American benchmark for composting toilets, established by NSF International (the National Sanitation Foundation) to ensure safety and performance. This certification shows a unit meets strict requirements for public health, including effective composting, odor control, and overall durability.

When a composting toilet meets NSF/ANSI Standard 41, you can be confident it has undergone rigorous evaluation and consistently delivers on its claims. Plus, many local regulators and building authorities look for this certification when approving composting toilets for installation—making it an important credential to have.

Most Sun-Mar composting toilets are certified to Standard 41. Click here to view our certification on NSF’s website.

Sun-Mar wants to ensure that there is a toilet that can fulfill every need or installation.

Sun-Mar composting toilets are designed to operate independently from traditional plumbing systems, making installation straightforward in virtually any location. They treat waste on-site, using natural processes to break down material without relying on water flush connections or sewer lines.

Instead of connecting to a main drain or septic system, Sun-Mar composting toilets utilize a Bio-drum™, where waste is safely processed and converted into compost.

No need for complex pipework or water supply—just a power source for models with fans or heaters. This flexibility is why Sun-Mar composting toilets can be found in cabins, boats, tiny homes, workshops, and remote properties where traditional plumbing would be difficult or expensive to install.

Absolutely, any type of toilet paper can be used in Sun-Mar units. It is a useful source of carbon for the compost.

For the outside shell or bowl liner of a self-contained toilet*, an ultra low-flush toilet, or an A/F Waterless toilet, Compost Quick and water, or a solution of vinegar and water, are the recommended cleaners.

You do not need to clean the Bio-drum™ unless bleach or some other chemical has been added to the drum by accident.

*For advice on cleaning the outside shells of electric self-contained or Central units, please call Sun-Mar’s customer service department at 1 888 341 0782, option 4.

Power washing is not recommended as this will damage electrical components.

All Sun-Mar toilets are built at our head office in Burlington, ON.

No, if installed and maintained as per instruction. Any odor is a sign that something is not quite right with either the compost, or the installation. Contact our customer service team with your serial number and we’d be glad to go over what is happening and help to resolve it.

For those needing the largest possible non-electric, waterless composting solution, there are extra-high capacity models available. Among these, options like the Sun-Mar Centrex 3000 NE stand out. Designed for situations with frequent or multiple users, these systems can support up to 5 adults full-time, or as many as 8 users on a weekend or vacation basis.

They’re built specifically for cabins, lodges, or any setting off the grid where power isn’t available but higher usage demands a robust setup.

None whatsoever. Chemicals such as bleach, essential oils, and common cleaners will disrupt, if not outright kill, the compost and are not recommended for use with Sun-Mar toilets. The only materials that should be used with any Sun-Mar toilet are the appropriate Compost Sure Green or Compost Sure Blue bulking materials, Compost Quick and Microbe Mix. These items are designed to work specifically with Sun-Mar’s system, promoting fast, complete composting while protecting the health of your unit.

Using only the recommended products helps ensure your Sun-Mar composting toilet operates odor-free and efficiently, keeping your compost healthy and making long-term maintenance easier. Consult your owner’s manual for specific instructions, or contact Sun-Mar’s customer service department for more information.

Compost Sure is a specially formulated bulking material made from coarse peat moss and chopped hemp stalk. Unlike homemade bulking mixes, Compost Sure offers a unique advantage: hemp stalks decompose more thoroughly than wood shavings or peat moss alone. This helps ensure a rich, well-aerated compost and saves you the hassle of creating your own mix.

For regular use, simply add about 1 cup per person per day. Compost Sure Green is ideal for self-contained units, while Compost Sure Blue is specifically designed for ultra low-flush systems, providing the right balance of organic carbon and moisture control to keep your compost aerobic and odor-free.

By sticking with these recommended materials and avoiding harsh chemicals, you’ll protect the living ecosystem inside your toilet—and keep everything running smoothly.

Yes. Composting may be affected, depending on the location and temperature where it is installed. If the self-contained toilet or Central unit is installed in a location with temperatures consistently below 50° F/15° C, the compost will go dormant and composting will stop, allowing the toilet to function as a holding tank. Removing compost from the drum to make room for some winter usage is recommended.

You never need to empty the Bio-drum™ completely. The compost in the drum contains the microbe colony that aerobically breaks down waste.

Typically in a seasonal installation, you would remove some compost to the finishing drawer to make room in the drum. The amount to be removed varies by unit and usage; contact Sun-Mar’s service department with any questions.

Non-electric units are best for these installations.

No problem, Sun-Mar has both electric and non-electric composting toilets available.

Non-electric Sun-Mar composting toilets are specifically designed for locations without continuous 110V supply—making them ideal for off-grid cabins, remote cottages, or any site where reliable power isn’t available. They use a 4″ vent at the top rear of the unit, acting much like a chimney on a wood stove, to create natural airflow for odorless operation—no fan or heater required.

If your installation requires bends in the vent or you expect heavy or full-time use, you can add an optional 12V fan powered by a small solar panel and a 12V marine battery, ensuring reliable performance even in more demanding situations.

Whether you’re running on solar, a generator, or have no electricity at all, there’s a solution to fit your needs.

Fans and thermostats are finite moving parts, and as such may wear out over time.

Typically, about as noisy as your average computer fan.

The maximum number of ultra low-flush toilets that can be used with a Central system is 3. However, it is important to remember that the number of toilets does not equate to how many people can use it. Each installation is different, and the capacity guidelines in your owner’s manual should be the determining factor.

The maximum recommended distance is 15 feet, with a drop of between 1/4″-1/8″ per foot. If your installation requires a run longer than the recommended distance, contact Sun-Mar customer service department regarding possible solutions.

No. We do not recommend adding food or garden scraps or greywater to the toilet as it will affect the composting process.