Sun-Mar composting toilets from Oasis Montana

Oasis Montana Inc.
Authorized Dealer for
Sun-Mar composting toilets

Call us!  406-777-4309
Fax: 406-777-4309
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Composting toilet Frequently Asked Questions (FAQs)

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Click on the questions below to reveal the answers.  If you don't see what you are looking for just give us a call, or email us at with your questions.

  • What about toilet paper?

    • Normal use with normal toilet paper is no problem and will be composted along with the waste.

  • Do composting toilets smell?

    • NSF only certifies composting toilets that produce no odor. All Sun-mar toilets are NSF approved.

    • The Sun-mar is designed so that air is constantly being drawn in and up the stack.

  • Will I need a sanitary permit before installing?

    • NSF standard #41 (waterless toilet) certification is all that's required by most local health departments for installation approval.

  • How does it work?

    • After initializing Sun-Mar's patented bio drum with start-up enzymes and some peat-based bulking material, all that is required is adding more bulking material at the rate of one cup per person per day of use, preferably after each use, and turning the bio-drum every 2-3 days for 4-6 revolutions.

    • The 3 chamber bio-drum does the rest by separating out and evaporating the liquids, Tumbling the drum optimizes mixing and aeration to create a uniform compost.

    • The finishing drawer allows the compost to complete the composting and sanitation process.

    • What is left is ready-to-use compost. Just pull out the finishing drawer and apply anywhere.

  • What happens when I have extra visitors or a party? Will it plug up?

    • Sun-Mar toilets are designed so that double the rated occupancy can be handled with no extra maintenance for brief periods of time.

  • I did everything according to the instructions and it doesn't seem to be composting. What's wrong?

    • Relax. Don't worry over it. Like a fine wine, composting takes some time. Did you add the initial microbe mix when you set it up? It can take a couple weeks or more to get started. If it freezes, it is not going to compost. Get some heat to it. (don't even try turning the drum if it is frozen). If it dries out completely, it isn't going to compost. Try adding more peat with some warm water. If it is too moist, not enough oxygen can get to it. Try adding more planer shavings, manually turning on any of the fans, if so equipped, and making sure you have the overflow drain attached. It is always helpful to have some extra Microbe mix to give it an added boost when necessary or when extra guests over tax the system.

  • How often does it need maintenance?

    • For continuous use just rotate the drum 4-6 revolutions every 2 or 3 days and add a cupful of peat mix per person per day of use.

    • Ideally it is best to add about 1/3 cup of bulking material each time you sit down for more then just a pee on the self- contained models so that there is more layering with the bulking material, rather then just throwing 4 or 5 cups on at the end of the day. You can facilitate this by keeping the bulking material handy in a covered trash can or some kind of container near the toilet.

    • For weekend usage, just rotate the drum 4-6 revolutions before leaving at the end of the weekend, in addition to adding a cup of peat mix per person per day.

    • Don't get over energetic about turning the drum; it won't make things happen faster. In fact, it has the effect of slowing the process down. Rotate the drum about 4-6 complete revolutions every 2-3 days and let the natural composting process do its thing.

  • Oh No! I ran out of Sun-Mar Bulking material, is there anything else I can use until I order more?

    • Yes, of course. Can you find a source of sphagnum moss and wood planer shavings? A nice mix is about 60% moss and 40% wood shavings (not saw dust). Is there a sawmill nearby or animal bedding available? Also, if your composting compartment is starting to get too damp, you can try adding some wood planer shavings to try balancing out the moisture content. As a tip, don't try using any treated wood, cedar, redwood, or other products that are resistant to natural decay.

  • Isn't it going to attract insects in my home?

    • Although flies may be attracted to sh*t, we are talking compost here. Active hot compost that is being covered with bulking material and being turned regularly is a different story. If you have fruit flies, fungus gnats, or whatever on your house plants, please keep them a distance from your self- contained composting toilet, maybe 15-20 feet or so.

    • If you are using local peat as part of your bulking material, make sure it is sterilized and free of any larvae.

  • I have the ability to have a standard toilet system. Why would I consider installing a composting toilet system instead?

    • Installation is quicker and cheaper.

    • It is greener because it uses little or no water and produces little or no liquid output and produces soil-enriching compost.

  • Why a Sun-Mar brand?

    • Sun-Mar is the only NSF standard 41 certified composting toilet for residential use.

    • Sun-Mar has its roots in composting toilets since 1971.

    • Sun-Mar's patented BioDrum technology has no equal.

    • Sun-Mar offers over 23 standard models to ensure you have a model that will fit your circumstances.

  • How does Sun-Mar's patented BioDrum work?

    • The Sun-Mar Bio-drum allows aerobic microbes to flourish, and work much more quickly to break down waste and toilet paper and convert them back to earth.

    • Waste and peat mix bulking material enter through the waste inlet port in the top of the drum. The drum is rotated periodically simply by turning a handle on the front (self-contained units) or side (central units). As the drum rotates, the input port closes automatically to keep the compost in the drum. Compost is extracted from the Bio-drum simply by releasing a drum lock and rotating the drum backwards. Compost then drops automatically through an open port in the Bio-drum directly into the compost finishing drawer. After rotating, the Bio-drum locks itself in a top dead center position, ready to receive new material.

  • What is the Warrantee on a Sun-Mar composting toilet?

    • Three years parts replacement, which covers defects in workmanship and materials throughout the U.S. (the warranty is 5 years in NY state).


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