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Sun-Mar Composting Toilets
Authorized Dealer
Composting Toilets for Off-Grid Living, Cabins, RVs & More
If you're looking for a Sun-Mar composting toilet, you're in the right place. We carry the full line -- from compact self-contained models like the GTG, to high-capacity systems like the Excel and Centrex. Whether you're off-grid full-time, living tiny, or just want a more sustainable setup, there's a Sun-Mar model that fits your life.
No Plumbing Required No Septic System North America's #1 Composting Toilet Free US Shipping
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Garden Composter by Sun-Mar
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🚛 Free Shipping to the Lower 48 States Questions about which model is right for your setup? Call us first.
1-844-945-3625
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No Plumbing, No Septic, No Problem
Sun-Mar composting toilets operate completely independently of your home's plumbing and sewer system. Install them in a cabin with no water hookup, an off-grid home, a tiny house, or anywhere traditional sewage infrastructure isn't an option or isn't wanted.
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The Bio-Drum™ Keeps Things Clean and Odor-Free
Sun-Mar's patented Bio-Drum™ technology continuously mixes and aerates waste, accelerating the composting process and preventing the anaerobic conditions that cause odors. Used correctly, a Sun-Mar toilet produces no smell. That's not a marketing claim -- it's how the chemistry works.
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Self-Contained or Centrex -- There's a Model for Every Layout
Self-contained units (Excel, GTG, Compact, Spacesaver) house everything in one unit -- the toilet and the composter. Centrex systems separate the composting tank to a basement or crawlspace, allowing you to use a standard-looking toilet bowl above. Both systems compost waste the same way.
Why Sun-Mar
Sun-Mar has been the leader in composting toilet systems for decades. Their toilets manage waste safely, naturally, and without plumbing or septic systems. Best part? No bad smells.
Sun-Mar's patented Bio-Drum™ technology kickstarts the composting process right inside the unit. Clean, simple, and surprisingly low-maintenance.
North America's #1 selling composting toilet.
Sun-Mar Model Comparison
All self-contained units house the toilet and composting drum in one piece.
| Model |  Sun-Mar ExcelBuy Now |  Sun-Mar Excel NEBuy Now |  Sun-Mar GTGBuy Now |  Sun-Mar CompactBuy Now |  Sun-Mar SpacesaverBuy Now |
| Dimensions | 33.25" × 22.5" × 33" | 31.5" × 22.5" × 33" | 19.8" × 15.75" × 24" | 28.5" × 21.5" × 33" | 30" × 19.5" × 23" |
| Capacity | 5 adults full-time / 8 seasonal | 5 adults full-time / 8 seasonal | Unlimited (removable canisters) | 1-2 adults full-time / 3 seasonal | 1 adult full-time / 3 seasonal |
| Electrical | Requires 110V AC Avg 150W | Non-electric Optional 12V fan | 12V DC fan (0.6W) 110/240V adapter incl. | Requires 110V AC Avg 125W | Requires 110V AC Avg 110W |
| Vent Size | 2" PVC | 4" PVC | None | 2" PVC | 2" PVC |
| Best For | Heavy residential / large families | Off-grid / no AC power | Tiny homes, RVs, boats | Smaller households / light seasonal | Tight spaces / closets |
| Highlights | High capacity, Bio-Drum, robust | Fully non-electric, natural draft odor control | Ultra-compact, urine-diverting, quick install | Compact Bio-Drum, light residential | Smallest footprint, electric evaporation |
Sun-Mar Centrex Central Composting System
Centrex systems place the composting tank in a basement or crawlspace, connecting to a standard-look toilet bowl above. All models require a 3" plumbing pipe and fittings (not included) to connect a 1-pint flush toilet.
| Model |  Centrex 1000Buy Now |  Centrex 1000 NEBuy Now |  Centrex 2000Buy Now |  Centrex 2000 NEBuy Now |  Centrex 3000Buy Now |  Centrex 3000 NEBuy Now |
| Weight | 50 lbs | 45 lbs | 97 lbs | 87 lbs | 102 lbs | 102 lbs |
| Dimensions (H × D) | 28" × 32.5" | 28" × 32.5" | 28" × 27" | 26.5" × 26.5" | 30.25" × 27.5" | 29.25" × 27.5" |
| Width / Clearance | 22.5" / 24.5" | 22.5" / 24.5" | 45.5" / 49" | 45.5" / 49" | 71" / 27" | 71" / 27" |
| Vent / Diffusor | 2" × 6 / 4" diff. | 2" × 6 / 4" diff. | 2" × 6 / 4" diff. | 4" × 5 / 6" diff. | 2" × 6 / 4" diff. | 4" × 5 / 6" diff. |
| Electrical | Max 2.5A / Avg 150W | Non-electric | Max 3.6A / Avg 200W | Non-electric | Max 3.6A / Avg 215W | Non-electric |
| Compost Bags | 1 | 1 | 2 | 2 | 2 | 2 |
Our Top Picks
Sun-Mar GTG
Great for vans, tiny homes, or cabins with limited space. Ultra-compact with unlimited capacity via removable canisters.
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Sun-Mar Excel
Perfect for full-time use in cabins, cottages, or off-grid homes. Handles up to 5 adults daily.
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Sun-Mar Centrex
Designed for larger groups, families, or setups with multiple bathrooms. Composting tank lives out of sight.
Get More InfoWhy Order Your Sun-Mar from Wild Oak Trail?
We're not just another online store. We're a family-run business that's been helping people live off the grid since 2017. We know these toilets inside and out, and we're here if you ever need advice, tech support, or someone to talk through your setup.
✅ Free shipping in the lower 48
✅ Expert support from real humans who use this stuff
✅ Fast, friendly service from a small team that actually cares
Not Sure Which Model Is Right for Your Setup?
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1-844-945-3625
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Found a better price? We'll match or beat it!
1-844-945-3625
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