TOTO Drake Two-Piece Toilet vs Kohler Highline Two-Piece Toilet: Which Should You Buy?
Comparisons4.6
We compared the TOTO Drake and Kohler Highline two-piece toilets: both hit MaP 1000 at 1.28 GPF. See flush systems, verified specs…
Read the guideComposting Toilet vs Flush Toilet: Off-Grid Comparison
A data-driven look at cost, water use, installation, odor, and long-term performance so you can choose the right system for your property, cabin, or off-grid build.
Quick Answer
A composting toilet wins for off-grid cabins, RVs, and water-scarce sites where no sewer or septic connection exists. A flush toilet wins in grid-connected homes where plumbing is already in place, odor management is critical, and household volume is high. Neither is universally better; the right answer depends entirely on your site, usage frequency, and regulatory environment.
What Is a Composting Toilet and How Does It Work?
A composting toilet is a self-contained or centrally vented system that processes human waste through aerobic decomposition, heat, and evaporation, producing a dry, humus-like end material without using water for transport. Most units separate liquid from solid waste at the bowl to control moisture and accelerate breakdown. Electric models add a heating element and fan to speed evaporation; non-electric models rely entirely on passive ventilation and bulking material such as peat, coconut coir, or wood shavings.
The biological process inside a composting toilet mirrors what happens in a garden compost pile. Aerobic bacteria break down organic matter when oxygen, moisture balance, and temperature are maintained within a workable range. Manufacturers such as Nature's Head, Sun-Mar, and Separett have refined the design over decades, but the core principle has not changed since early Scandinavian installations in the 1960s.
Self-contained composting toilets house the composting chamber directly below the seat. Central or remote systems route waste through a pipe to a larger drum located in a basement or crawlspace, which is ideal for higher-use households. Capacity ratings matter: a typical self-contained unit is certified for two to three full-time users, while central units can handle four to six.
Editorial Take
Moisture management is the single biggest failure point in composting toilets. Owners who add too much liquid or insufficient bulking material report odor and incomplete breakdown. Proper liquid diversion and a strict bulking-material routine solve 90 percent of complaints found in aggregated owner reviews on platforms such as Amazon and RV forums.
How Does a Standard Flush Toilet Compare in Water Use?
A standard pre-1994 flush toilet uses 3.5 gallons per flush (GPF) or more, while EPA WaterSense-certified toilets must use 1.28 GPF or less and must pass MaP testing at 350 grams minimum to earn certification. Modern high-efficiency models such as the TOTO Drake II and the American Standard Champion 4 achieve 1,000-gram MaP scores at 1.28 GPF, delivering powerful waste removal with 20 percent less water than the federal 1.6 GPF maximum. A composting toilet uses zero water per flush, making it the clear winner in water conservation on paper, but that comparison is only meaningful where water supply is genuinely limited.
For a household of four people using a toilet an average of five times per day per person, the math works out as follows. At 1.6 GPF the household consumes roughly 11,680 gallons of water per year on toilet flushing alone. At 1.28 GPF that figure drops to approximately 9,344 gallons. A composting toilet reduces that figure to zero, though it requires electricity (30 to 80 watts for electric models) or passive venting systems and periodic addition of bulking material costing roughly $20 to $60 per year.
EPA WaterSense labels are displayed on toilets from all major brands. TOTO's Aquia IV dual-flush model uses 1.0 GPF on liquid waste and 1.28 GPF on solid waste. Kohler's Cimarron achieves a MaP score of 1,000 grams at 1.28 GPF. American Standard's Cadet 3 earned WaterSense certification in its 1.28 GPF variant. Gerber's Viper reaches 1,000 grams on MaP testing at 1.28 GPF. These are credible, publicly verified numbers, not marketing claims. See the best flushing toilets guide for ranked picks across all categories.
| Factor | Composting Toilet | Flush Toilet (1.28 GPF WaterSense) |
|---|---|---|
| Water per flush | 0 gallons | 1.28 GPF (federal max 1.6 GPF) |
| Annual water use (4 people, 5 flushes/day) | 0 gallons | ~9,344 gallons |
| Upfront unit cost (typical range) | $800 to $2,500+ | $150 to $900 |
| Installation cost | $200 to $800 (electric/vent only) | $150 to $500 (if rough-in exists) |
| Sewer/septic connection required | No | Yes |
| Ongoing annual cost | $20 to $100 (bulking material + electricity) | Water/sewer charges vary by municipality |
| Maintenance frequency | Every 3 to 6 weeks (liquid tray); 1 to 4x/year (solids) | Annual wax ring inspection; occasional flapper |
| Odor control | Good when properly maintained; fails if mismanaged | Excellent; water seal prevents sewer gas |
| Regulatory approval (USA) | Varies by state and county; some prohibit residential use | Universally approved |
| Best use case | Off-grid, remote cabins, boats, RVs, water-scarce land | Grid-connected homes, rentals, high-traffic use |
What Are the Real Installation Requirements for Each System?
A flush toilet requires a 3- or 4-inch drain line connected to a municipal sewer or approved septic system, a cold-water supply line at 20 to 80 PSI, and a properly positioned floor flange. A composting toilet requires only a 2- to 4-inch vent stack routed through the ceiling and roof, plus a 110V outlet for electric models; it does not need a water supply or drain connection, making it viable in any location where a roof penetration is possible.
For new construction in a remote location, the difference in site infrastructure is enormous. Installing a septic system for a flush toilet in rural terrain typically costs $5,000 to $25,000 depending on soil percolation tests, tank size, and drain field length. Permits are mandatory, inspections are required, and some jurisdictions impose setback rules that make installation impossible on small or irregular lots. A composting toilet eliminates all of that infrastructure, which is why the total cost of ownership can favor composting systems over a 10-year horizon even though the unit itself costs more upfront.
For an existing grid-connected home, the calculation reverses. The rough-in plumbing is already in place. Swapping a toilet takes under an hour and the unit costs $150 to $900 depending on the model. Adding a composting toilet to an existing bathroom would still require a vent stack installation and potentially a local permit; in most municipalities a flush toilet remains the only code-compliant option for primary residential bathrooms.
Related reading: toilet rough-in sizes explained and how to install a toilet step by step.
Editorial Take
Always verify local health codes before purchasing a composting toilet for residential use. Some states, including several in the southeastern United States, restrict or prohibit waterless composting systems in permanent dwellings regardless of how remote the property is. The National Sanitation Foundation (NSF) Standard 41 certification is the most commonly required approval for composting toilets used in the United States, and only systems carrying that mark are accepted in most jurisdictions that do allow them.
Which System Has Better Odor Control?
A flush toilet's water trap creates a constant liquid seal that blocks sewer gases from entering the bathroom; odor control is passive, reliable, and requires no user action. A well-maintained composting toilet with proper venting and correct bulking-material ratios should be nearly odorless at the seat, but any disruption to the moisture balance, vent airflow, or composting process can produce noticeable ammonia or sulfur odors that a flush toilet will never generate under normal use.
The vent fan in an electric composting toilet creates negative pressure inside the composting chamber, so air flows down into the drum rather than up toward the user. This is effective when the fan operates continuously, which most manufacturers recommend. Power outages, fan failures, or improper vent routing (too many bends, insufficient rise above the roofline) all degrade this performance. Owner reviews across Nature's Head, Sun-Mar Excel, and Separett Villa models consistently show that odor is the top complaint when units are improperly installed or maintained, but also the top praise point when installation is done correctly.
Flush toilet odor comes primarily from the bowl itself after use, not from the system. Regular cleaning with an appropriate bowl cleaner addresses this. The water trap eliminates methane and hydrogen sulfide from the drain stack. American Standard's EverClean glaze and TOTO's CeFiONtect glaze both reduce bacterial adhesion to the porcelain, which is the main source of lingering bowl odor between cleanings.
What Does Long-Term Maintenance Actually Look Like for Each Option?
A flush toilet requires virtually no scheduled maintenance beyond periodic cleaning; the wax ring seal typically lasts 20 to 30 years, flappers cost a few dollars to replace every few years, and professional intervention is rarely needed unless a clog or leak develops. A composting toilet requires emptying the liquid diversion bottle or tray every one to three weeks depending on usage, adding bulking material after each solid use, and removing the finished compost from the drum two to four times per year, a process that takes 10 to 15 minutes but requires gloves and a compost-handling routine some owners find unpleasant.
The maintenance gap is significant for households with multiple occupants or for anyone renting out a vacation cabin. A flush toilet connected to a municipal sewer is essentially maintenance-free for years at a time. A composting toilet rewards disciplined, attentive owners and punishes neglect with odor, incomplete breakdown, and potential overflow of the liquid compartment. For seasonal cabins used by different guests, the training and discipline requirement is a real operational challenge.
On the other hand, flush toilets do fail in ways that composting toilets never can. Supply line failures, flapper leaks, and wax ring failures are common and can cause water damage. MaP testing from the MaP Flush Testing program (available at map-testing.com) documents performance consistency across 1,000-gram test loads, but it cannot predict plumbing failures. The Woodbridge T-0001, for example, carries strong MaP results but user reviews mention occasional supply line quality issues, illustrating that the toilet unit itself is only one part of a broader plumbing system that can fail.
For context on choosing reliable flush models, see best toilets for no-clog performance.
Editorial Take
The best predictor of composting toilet satisfaction in aggregated reviews is not the brand -- it is the owner's willingness to follow the maintenance schedule. Users who treat it like a flush toilet and avoid reading the manual report the worst experiences. Users who commit to the bulking-material routine and quarterly emptying report high satisfaction, even in full-time residential use. That human factor matters more than any specification comparison.
Is a Composting Toilet Legal and Permitted in My Area?
Composting toilet legality in the United States varies at the state, county, and sometimes municipal level; as of 2026 they are explicitly permitted as a primary sanitation option in states including Oregon, Washington, Vermont, and Montana, conditionally permitted in many others, and effectively prohibited as the sole toilet in permanent dwellings in some southeastern and midwestern states. The NSF/ANSI 41 standard is the primary certification buyers should look for, and a local health department inquiry is the only reliable way to confirm compliance requirements for a specific address.
In many jurisdictions a composting toilet is approved as a supplemental toilet alongside a conventional flush toilet but not as the only sanitation system in a primary residence. Tiny homes, cabins on recreational land, and structures classified as accessory dwelling units often have more flexibility than primary residences. RVs and boats fall under different regulatory frameworks entirely; the Coast Guard and state boating agencies govern marine sanitation devices separately from residential codes.
The end product of a properly functioning composting toilet is technically a Class A biosolid according to EPA standards when temperatures and retention times are met, but most jurisdictions do not allow homeowners to apply it to vegetable gardens or food-producing land even if the material tests clean. Check your county extension office for local guidance on finished compost disposal.
| Situation | Recommended System | Key Reason |
|---|---|---|
| Off-grid cabin, no septic | Composting toilet | Eliminates $10K+ septic installation |
| Full-time primary residence on municipal sewer | Flush toilet | Code required; zero maintenance burden |
| Seasonal vacation cabin (occasional use) | Composting toilet | No freeze risk to plumbing; lower operating cost |
| High-traffic rental property | Flush toilet | No guest training required; reliable performance |
| Boat or marine vessel | Composting toilet (NSF-certified) | No overboard discharge; simpler than Type I/II MSD |
| Water-scarce desert property (with sewer) | Dual-flush toilet (1.0/1.28 GPF) | Balances water savings with code compliance |
| Tiny home on a permanent foundation | Varies by county | Check local code before purchasing either system |
What Are the Best Flush Toilets for Water Efficiency If You Stay on the Grid?
For water-conscious households connected to municipal plumbing, the TOTO Aquia IV (1.0/1.28 GPF dual-flush) and the TOTO Drake II (1.28 GPF, 1,000-gram MaP score) are the two most consistently recommended models based on MaP testing results and long-term owner reviews. American Standard's Champion 4 and Cadet 3 both earn 1,000-gram MaP scores at 1.28 GPF and carry EPA WaterSense certification, representing strong alternatives at a lower price point.
The TOTO Drake is a two-piece toilet that uses TOTO's G-Max flushing system with a 3-inch flush valve and wide 2-1/8 inch trapway. The Drake II upgrades to the Tornado Flush system with a 3-inch double-cyclone nozzle that scours the bowl while using 1.28 GPF. Both models appear consistently at the top of MaP testing databases for their respective GPF ratings.
Kohler's Highline Arc and Cimarron both achieve 1,000-gram MaP performance and carry WaterSense certification. The Cimarron's Class Five flushing technology uses a 3-1/4 inch piston-action canister flush valve rather than a traditional flapper, which Kohler claims reduces leak risk over time. Swiss Madison's Well Made Forever toilets and Gerber's Viper line offer budget-accessible WaterSense-certified options with verified MaP scores above 500 grams, though typically below 1,000 grams in that price tier.
See the full water-efficient toilets guide for ranked comparisons with MaP scores and GPF ratings side by side.
Editorial Take
EPA WaterSense certification alone does not guarantee strong flushing performance. WaterSense requires only a 350-gram MaP minimum. Always check the MaP Testing database at map-testing.com directly for the exact model you are considering. The gap between a 350-gram model and a 1,000-gram model at the same 1.28 GPF is the difference between frequent double-flushing and reliable single-flush performance, which can actually erase the water savings advantage of a low-GPF toilet in real-world use.
How Much Does Each System Actually Cost Over 10 Years?
For an off-grid installation requiring a new septic system, a flush toilet system typically costs $6,000 to $27,000 over 10 years once septic installation, maintenance, and pump-outs are included; a composting toilet in the same setting typically costs $1,500 to $4,500 total including the unit, installation, and 10 years of bulking material. For a grid-connected home where plumbing already exists, the flush toilet wins on total cost by a wide margin because the composting toilet's higher unit price provides no infrastructure savings.
Breaking down the off-grid 10-year cost for a flush toilet: septic system installation runs $5,000 to $20,000 depending on soil and design; annual pump-outs average $250 to $500; the toilet unit itself costs $200 to $600; water usage if on a well and pressure system adds pump operating costs. Over 10 years, total costs range from approximately $7,500 on the low end to $27,000 or more on a difficult site.
For the composting toilet in the same off-grid scenario: unit cost of $900 to $2,500 (Nature's Head runs $900 to $1,200; Sun-Mar Excel NE runs $1,400 to $2,000; central systems can reach $3,000+); installation including vent stack runs $200 to $800; bulking material at $30/year over 10 years adds $300; electricity for the fan runs roughly $30 to $80 per year. Total 10-year cost: approximately $1,930 to $5,400, a savings of $3,000 to $15,000+ versus flush in an off-grid scenario.
In a grid-connected home where rough-in plumbing is already present, the composting toilet's infrastructure advantage disappears entirely. A TOTO Drake II at $350 to $500 installed beats a Nature's Head at $900 to $1,500 installed on day one, and the flush toilet carries zero ongoing bulking-material or manual-emptying costs.
Frequently Asked Questions
Do composting toilets actually smell bad?
A properly installed and maintained composting toilet is nearly odorless at the seat because the vent fan creates negative pressure that draws air down into the drum rather than up toward the user. Odor problems arise from incorrect moisture balance, insufficient bulking material, inadequate vent rise above the roofline, or fan failure. Most negative odor reviews can be traced to one of these installation or maintenance errors rather than an inherent flaw in the technology.
Can a composting toilet be used as the only toilet in a house?
In many US jurisdictions, yes -- but not all. States such as Oregon, Washington, and Vermont explicitly allow composting toilets as primary sanitation in residences. Others require a backup conventional system or do not permit composting toilets in permanent dwellings at all. Always check with your county health department before purchasing.
What happens to the waste in a composting toilet?
Aerobic bacteria break down solid waste into a dry, humus-like material over weeks to months depending on temperature, moisture, and usage volume. The liquid diversion system routes urine to a separate container or external drain. The finished solid material is typically removed and buried in a compost pile or disposed of per local regulations; it should not go into a standard garbage bin in most municipalities.
How often do you empty a composting toilet?
The liquid tray or bottle in a self-contained unit typically needs emptying every one to three weeks for one to two full-time users; more often for larger households. The solid composting drum typically needs servicing two to four times per year for full-time use. Seasonal or occasional-use cabins may go six months between solid chamber cleanings if usage volume is low.
What is the best composting toilet for an off-grid cabin?
Nature's Head is the most consistently praised self-contained composting toilet in aggregated owner reviews for small cabins and boats, largely due to its robust construction, active liquid separation, and strong after-sales support. Sun-Mar Excel NE (non-electric) is preferred where power is unavailable. For higher-use cabins, Sun-Mar's central systems or BioLet models offer larger capacity.
What is EPA WaterSense and how does it relate to flush toilets?
EPA WaterSense is a voluntary labeling program administered by the US Environmental Protection Agency. Toilets earning the WaterSense label must use 1.28 GPF or less and must pass independent third-party performance testing at a minimum 350-gram MaP score. As of 2026, over 2,000 toilet models carry WaterSense certification. The label appears on models from TOTO, Kohler, American Standard, Gerber, Woodbridge, Swiss Madison, and most major brands.
What is MaP testing and why does it matter?
MaP (Maximum Performance) testing is an independent flush-performance protocol that measures how many grams of simulated waste a toilet can clear in a single flush. Scores run from under 100 grams (very poor) to 1,000 grams (the maximum tested). Toilets with 600-gram MaP scores or higher are generally considered strong performers; 1,000-gram scores indicate the highest tested performance. MaP results are publicly searchable at map-testing.com and are the most objective single metric for comparing flush toilets.
Can you use toilet paper in a composting toilet?
Yes, but it should be unbleached, recycled, or rapid-dissolve toilet paper in modest quantities. Standard toilet paper does compost, but heavy use slows the process and can unbalance moisture levels. Some composting toilet users prefer to use a small wastebasket for paper to speed up the composting cycle, particularly during high-use periods.
Do you need electricity for a composting toilet?
Not all models require electricity. Non-electric composting toilets such as the Sun-Mar Excel NE and Separett Weekender use passive ventilation through a correctly sized vent stack. Electric models such as the Nature's Head (optional fan upgrade) and Sun-Mar Excel AC use a low-wattage fan (typically 12 to 80 watts) to create consistent negative pressure, which generally produces better odor control and faster evaporation than passive systems.
How does a dual-flush toilet compare to a composting toilet for water savings?
A dual-flush toilet such as the TOTO Aquia IV (1.0/1.28 GPF) saves significant water versus a conventional toilet but cannot match the zero-water use of a composting toilet. In a 4-person household, a dual-flush toilet might use 7,000 to 9,000 gallons per year; a composting toilet uses none. The practical value of that difference depends on whether your water comes from a municipal supply (lower impact) or a well with limited capacity (higher impact).
What is the lifespan of a composting toilet?
Well-maintained composting toilets from reputable manufacturers typically last 10 to 20 years. The rotating drum mechanism and fan motor are the most common wear points. Nature's Head and Sun-Mar both offer replacement parts and warranty service; Nature's Head carries a 5-year warranty on the housing and 1-year on electrical components. A quality flush toilet such as the TOTO Drake or Kohler Cimarron can last 30 to 50 years if the porcelain is not chipped and internal components are periodically serviced.
Is a composting toilet sanitary?
Yes, when functioning correctly. The composting process generates heat (up to 140 degrees Fahrenheit in active piles) that kills pathogens. NSF/ANSI 41-certified units have passed testing protocols confirming that the end material does not pose a public health risk under specified operating conditions. The liquid diversion compartment is handled separately and more frequently, which is the most direct contact point for users.
Can a composting toilet handle feminine hygiene products or medication?
No. Manufacturers universally advise against disposing of tampons, pads, medications, cleaning wipes, or other non-biodegradable materials in composting toilets. These items do not compost, can clog the drum mechanism, and may contaminate the end product. A small sanitary bin near the toilet is standard practice in any composting toilet installation.
What flush toilet brands have the best long-term reliability?
TOTO and Kohler consistently rank highest in long-term owner satisfaction surveys and professional plumber recommendations. TOTO's Drake and Drake II are among the most frequently specified toilets in commercial and residential settings precisely because of their documented MaP performance and parts availability. American Standard's Champion 4 is praised for its Class Five flush valve and wide trapway that reduce service calls. Gerber is less well known but carries strong MaP scores and commercial-grade build quality at a mid-range price.
Does a composting toilet reduce my property's environmental impact?
For off-grid sites, yes substantially. It eliminates the need for a septic system (which requires land disturbance, ongoing chemical treatment, and pump-out transport) and removes all toilet-related water demand from the property's supply. For grid-connected homes, the environmental benefit is more nuanced: municipal wastewater treatment plants often recover energy and nutrients from sewage, so switching to a composting toilet on a treated municipal system has a smaller net environmental benefit than it might appear.
Can I install a composting toilet myself?
Self-contained models such as the Nature's Head are designed for DIY installation. The main tasks are cutting a vent hole through the wall or ceiling, routing the vent pipe to above the roofline, and plugging in the fan. No plumbing license is required for the composting toilet itself, though local permitting for the vent penetration may apply. Central composting systems with larger drums are more complex and may benefit from professional installation to ensure correct vent sizing and drainage of the liquid output.
What bulking material works best in a composting toilet?
Coconut coir (coco peat) is the most widely recommended bulking material: it absorbs moisture efficiently, has a neutral pH, composts readily, and is sold in compressed bricks that expand to large volumes. Peat moss works but raises sustainability concerns given its slow-renewing nature. Fine wood shavings or commercial composting toilet mix are also effective. Coarse sawdust is less ideal because it can impede the mixing mechanism in some drum designs.
Is a composting toilet a good option for a tiny home?
Often yes, but it depends on local zoning. Tiny homes classified as RVs can typically use composting toilets without issue. Tiny homes on permanent foundations in residential zones may be subject to the same plumbing code requirements as conventional homes. Many tiny home builders choose composting toilets specifically to avoid the cost and complexity of septic hookup, but this approach requires advance verification with the relevant authority having jurisdiction.
What happens to a composting toilet in winter in cold climates?
Cold temperatures slow the composting process and can halt it entirely below approximately 55 degrees Fahrenheit, the lower threshold for active aerobic bacterial activity. In unheated off-season cabins, the drum will pause composting but will not freeze or overflow if the unit is not in use. When the cabin warms up and use resumes, composting activity restarts. Electric models with heating elements maintain better performance in marginal temperatures, and central systems located in basements benefit from ambient building heat.
Can a composting toilet and a flush toilet coexist on the same property?
Yes, and this is actually a common configuration for properties that want to reduce septic load or test composting technology without fully committing. A composting toilet might serve a remote outbuilding, workshop, or guest cabin while the main home retains a conventional flush toilet on a septic or sewer connection. This arrangement also satisfies jurisdictions that require a conventional toilet in the primary dwelling while allowing supplemental composting units elsewhere on the property.
Sources
- EPA WaterSense, epa.gov/watersense
- MaP flush testing, map-testing.com
- Manufacturer published specifications
- NSF International, NSF/ANSI Standard 41: Non-Liquid Saturated Treatment Systems, nsf.org
- Nature's Head composting toilet documentation, natureshead.net
- Sun-Mar composting toilet specifications, sun-mar.com
- TOTO USA product data sheets, totousa.com
- Kohler product specifications, kohler.com
- American Standard product data, americanstandard-us.com
Our Verdict
If your property has no sewer or septic connection, a composting toilet is almost certainly the right choice: it eliminates $5,000 to $20,000 in infrastructure cost, uses zero water, and performs reliably for a decade or more when maintained correctly. If you are connected to municipal plumbing, a high-efficiency flush toilet from TOTO, Kohler, or American Standard -- with a MaP score of 800 grams or above at 1.28 GPF and an EPA WaterSense certification -- gives you the best balance of flushing performance, water savings, and long-term reliability without any maintenance burden. The composting vs flush toilet debate is not a close call once site conditions are known; it is primarily an infrastructure and regulatory question, not a preference question.
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