The Camco Rhino 21-gallon tote tank is the best portable waste tank for RV boondocking for most people, and the Barker 4-Wheeler 42-gallon is the one to buy if you camp as a full-time household and haul your waste over rough ground. Both roll rather than lift, both empty through a side valve, and both come with the fittings that most people forget to buy separately. Below I break down eight tanks side by side so you can match capacity to your black tank instead of guessing.
I know the failure this category produces because I have watched it happen. A rig with a 27-gallon black tank fills up on day nine of a two-week plan, the nearest dump station is 20 miles down a washboard forest road, and suddenly you are breaking camp early or making a mess you regret. A portable waste tank, also called a tote tank or a honey wagon, is a wheeled holding tank you park beside your RV and transfer black and grey water into, so you can empty it later at a dump station without moving the whole rig.
That is the whole concept, and it is genuinely useful. It decouples how long you can stay put from how close the nearest sewer connection happens to be. A 35-gallon tote has been reported to buy roughly five or six extra days off grid; the 42-gallon Barker has been reported to buy closer to six. In 2026 I have gone through eight tanks that cover the range from a 10-gallon hauler to a 42-gallon four-wheeler, including the wheel and valve details that actually decide whether a tote is usable in the field. If you are still assembling the rest of your rig, our picks for the best RV batteries and the best RV fridges cover the other two things that decide how long a boondock lasts.
Top 3 Portable Waste Tanks for RV Boondocking in October 2026
Camco Rhino 21-Gal Tote Tank
- 21 gallon capacity
- No-flat wheels
- UV-stabilized blow-molded HDPE
- Full accessory kit
Barker 4-Wheeler 42 Gallon
- 42 gallon capacity
- Front double swivel wheels
- 3-inch side waste valve
- Pneumatic tires
Barker 31342 30 Gallon
- 30 gallon capacity
- Steel trailer hitch handle
- Visible fluid level
- Universal fit
One quick note before the full list, because it catches nearly everybody. The Camco Rhino comes in several sizes, and the 15-gallon and 21-gallon versions use a low drain hole rather than a full side gate valve. If you buy one of those expecting a gate valve, you will be disappointed. The 21-gallon unit we tested does include a drain hole and an integrated tank rinser, which is what makes the rest of this roundup simpler.
All 8 Portable Waste Tanks at a Glance for October 2026
| Product | Specs | Action |
|---|---|---|
| Camco Rhino 21-Gal Tote Tank |
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Check Latest Price |
| Barker 4-Wheeler 42 Gallon |
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| Barker 31342 30 Gallon |
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Check Latest Price |
 Thetford SmartTote2 12 Gallon |
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Check Latest Price |
 VINGLI 10 Gal Tote Tank |
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 Thetford 40510 Smart 18 Gallon |
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Check Latest Price |
 RecPro 36 Gallon Waste Tank |
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 Venustank 30 Gallon 2 Wheel Tote |
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Check Latest Price |
Nominal capacity is not the same as usable capacity, and we will come back to that in the buying guide. A tote never empties completely, so a tank marketed at 36 gallons gives you a bit less than that in practice. Owners who track their own consumption report that a 35-gallon tote bought roughly five to six extra boondocking days, which is a better way to compare these than the number stamped on the side.
1. Camco Rhino 21-Gal Tote Tank – Best Overall Portable Waste Tank
Camco Rhino 21-Gal RV Portable Tote Tank – Made in the USA
21 gallon
34.5 lb empty
No-flat wheels
20 x 12.5 x 40 inch
Made in USA
Pros
- No-flat wheels and an oversized handle
- Complete kit with sewer hose grey water hose elbows caps and tow adapter
- UV-stabilized blow-molded HDPE
- Integrated tank rinser and drain hole
- Two year limited Camco warranty
Cons
- Ribbed carry handle is uncomfortable on a full tank
- Heavy to move when full
- Bulky 40.63 inch footprint for storage
The Rhino 21 is the tank I recommend to people who ask me for one number to remember. It has the highest review volume of anything in this roundup by a wide margin, and that volume matters in a category where failure is expensive: nearly 27k owners have left feedback on this specific listing, which means the oddities get filtered out and the real complaints get repeated. What they praise most is the wheel package and the fact that the kit arrives complete.
You get no-flat wheels, an oversized carry handle, and a steel tow adapter, so the tank rolls across gravel or follows a truck bed when the dump station lane is too narrow to back into. It is made from UV-stabilized blow-molded HDPE in the USA, which is the material I want for a tank that sits in full sun on a desert site for two weeks. The 2-year limited warranty from Camco is also the longest warranty published in this group.
Dimensions are listed as 20.125 by 12.5 by 40 inches in the product detail section and 40.63 by 40.63 by 20 inches in the technical block, so measure your storage bay before you commit. Empty weight is 34.5 pounds. Add liquid at 8.34 pounds per gallon and a full 21-gallon tote comes to roughly 210 pounds, which is a two-person lift in most cases. Owners have been running these through multiple winters, which says something about the wall thickness.
Cleaning is straightforward because the interior is smooth and there is an integrated tank rinser with a drain hole rather than a deep sump. You can run a rinse wand and a treatment through it, then roll it to a drain. The ladder hook and the tie-down strap grooves mean you can hang it or strap it rather than letting it wander around a campsite.
Why we picked the Rhino 21 over the 36-gallon version
Two reasons. First, the 21-gallon loaded weight stays in a range one strong person can roll and two people can tip, and the 36-gallon sibling pushes past 300 pounds loaded. Second, 21 gallons of usable capacity still extends most two-week trips by several days, so you are not buying capacity you will never use.
It is also the tank most often named as the consensus pick by owners on r/RVLiving and the Jayco Owners forum, and those are the two places where I would look before buying anything in this category. That is not a substitute for testing, but a product that survives tens of thousands of reviews and repeated forum mentions is a safer bet than a newer listing with a handful of ratings.
Where the Rhino 21 falls short
The most repeated complaint is the carry handle. It is ribbed and hollow on one side, and owners note it becomes uncomfortable to grip when the tank is full. If you have grip strength issues, plan on the wheels or the tow adapter doing the work instead of your arms.
Second, the footprint is tall. At 40 inches in one dimension it does not tuck into a small pass-through storage bay, so you need a ladder, a truck bed, or a dedicated compartment. Third, and this catches people out constantly, the 15 and 21 gallon models use a low drain hole design rather than a side gate valve, so draining is a tip-and-hold operation rather than a valve pull.
2. Barker 4-Wheeler 42 Gallon – Best Portable Waste Tank for Maximum Capacity
Barker 4-Wheeler Tote Tank – 42 Gallon Capacity (30844)
42 gallon
47 lb empty
Front double swivel wheels
Pneumatic tires
45 x 24 x 14 inch
Pros
- Front-mounted double swivel wheels on a heavy-duty plate
- 3-inch side-discharge valve means no lifting to empty
- Combo vent and rinse connection
- Blow-molded polyethylene with zinc-plated steel and aluminum hardware
- Removable metal handle for towing
Cons
- The supplied pneumatic tires crack and are awkward to replace
- Tank height can exceed some RV dump ports
- Handle can unclip from the hitch ball when towing without a strap
If two people use the shower every morning, the Barker 42 is the tank that ends the mid-trip dump runs. At 42 gallons it swallows a full RV holding tank in one transfer, and owners running long dispersed trips point to it as the choice for exactly that reason. It is also the tank most often recommended for full-time boondockers who move across rough ground, which is what the tire package is about.
The front double swivel wheels mounted on a heavy-duty plate are the standout feature. A conventional tote has two fixed wheels at one end, so you drag the opposite end sideways. Swivels let you push it in any direction, and on a forest road with ruts and rock you will feel the difference immediately. The 3-inch side-discharge waste valve means you roll it under the dump port and pull a handle instead of lifting 350-plus pounds over your head.
Construction is blow-molded polyethylene with zinc-plated steel and aluminum hardware, listed at 47 pounds empty and 45 by 24 by 14 inches. A combo vent and rinse connection on top handles both venting and flushing, and the removable heavy-duty metal handle converts it to a towable unit. The model number is 30844 and it has been in production since 2007, which tells you how settled the design is.
Loaded, a full 42-gallon Barker is around 400 pounds. That is not a lift. Owners build ramps to push a loaded tote into a truck bed rather than trying to hoist it, and that is the approach I would take. If you plan to tow the tank to a dump station instead of carrying it, strap the handle to the hitch ball. Owners report it popping loose on downhill grades without one.
What the 42 gallons actually buys you
Roughly six extra days off grid for a household using black and grey water, based on owner reports of consumption tracking. The nominal 42 gallons is also a nominal figure. Waste coats the walls and a residue stays in the bottom, so treat the number as an upper bound rather than a target.
The trade is mobility for capacity. At 45 inches long and 47 pounds empty, this is the largest, heaviest object in the roundup. It suits a family of four or a full-time rig with a truck bed or a place to store 45 inches of tank. It does not suit a small trailer with a plastic storage bay.
Where the Barker 4-Wheeler gets annoying
The pneumatic tires are the top complaint. Reviewers say they crack with age and UV exposure and are a fiddly replacement, which is exactly the failure mode that strands you 20 miles from a dump station. Budget for a tire swap, or check them before every long season. Owners also note that the tank can stand taller than some RV dump ports, so you may not be able to get the valve under the port at all.
One more practical note: the level gauge on this model has been reported as restricting airflow and popping off under pressure. Treat the gauge as a convenience, not as your only overfill protection.
3. Barker 31342 30 Gallon Tote – Best Mid-Size Portable Waste Tank
Barker (31342) Tote Tank – 30 Gallon Capacity
30 gallon
35 lb empty
Steel hitch handle
39 x 27 x 39 inch
Universal fit
Pros
- Dumps without moving the RV or trailer
- Thick-wall construction built for heavy use
- Heavy gauge steel trailer hitch handle
- Visible fluid height reduces overfilling
- Saves setup time at every dump
Cons
- Gets very heavy when full
- Only one carry handle makes truck-bed loading awkward
- Wheel end caps and axle nuts can fail while towing
- No sewer hose included
The 31342 is the middle of the Barkers and, for a lot of rigs, the right answer. Thirty gallons is enough that a couple of people can stretch a trip by close to a week, and at 35 pounds empty it is meaningfully lighter than the 42. If your RV has a 27-gallon black tank, a 30-gallon tote is close to a one-to-one match and you can empty once and reset.
The steel trailer hitch handle is the piece that makes this tank work. It is heavy gauge, so you can drag or tow the loaded tank to a dump station without any lifting. The visible fluid height is genuinely useful when you are filling by hose, because you can see the level rise instead of guessing, and overfilling is the single most common mistake new tote owners make.
Dimensions are listed at 39 by 27 by 39 inches with a 35-pound empty weight, and it is a universal fit for RV and trailer grey or black water. It is a simple design, which is both its strength and its limit: fewer moving parts means fewer things to break, but also fewer features. There is no self-storing hose and no integrated rinser, so you are assembling your own kit.
Reviewers rate the thick-wall construction as genuinely heavy duty and say it holds up under repeated fill and dump cycles. The time saving is the real selling point. Owners describe breaking down camp, driving the trailer to a site, and waiting in line as the thing they hate most, and a tote removes that from the trip entirely.
Who this 30-gallon tote suits
A couple or small family, weekend dry campers, and anyone with a 27 to 30 gallon black tank who wants a one-to-one capacity match. At roughly 285 pounds loaded it is still heavy, but the hitch handle means you roll it rather than carry it. Pair it with a short non-potable rinse hose and a 4-in-1 adapter and you have a complete setup.
It also suits people who dump every couple of days rather than every two weeks, because the 30-gallon capacity is quick to move through and quick to rinse.
What to fix before your first trip
No sewer hose is included, and reviewers say some of the supplied hook ends seal better than others, so budget for your own. That is not a criticism of the tank, it is just how this model is sold.
The wheel end caps and axle nuts are the weak point according to owners, who have swapped in locking pins and solid tires. There is also only one carry handle, so getting a loaded tote into a truck bed is awkward. Build a ramp or plan to roll it at the site. Check the rating spread too: 4.5 stars is strong, but the 5 percent share of 1-star reviews coincides with reports about these wheel and axle parts.
4. Thetford SmartTote2 12 Gallon – Best Portable Waste Tank for Small Rigs
SmartTote2 Portable RV Waste Tote Tank – 2 Wheels – 12 Gallon – Thetford 40505
12 gallon
10.6 lb empty
Two wheels
Polypropylene
18.5 x 10.5 x 30.62 inch
Pros
- Light enough to lift into a truck bed by hand when full
- Low-profile inlet suits trailers with low dump valves
- Seals well with standard sewer hose fittings
- Arrives fully assembled with vent and hose caps
- Fits under a camper for storage
Cons
- No sewer hose included despite listing imagery
- No overfill indicator so filling needs care
- Wheels reported popping off in transit
- Instructions cover larger SmartTote2 models
This is the small-rig answer. At 10.6 pounds empty, it is one of the few tanks in the roundup that one person can lift into a truck bed when full. A full 12-gallon tote comes to roughly 111 pounds, which is a real two-hand carry rather than a hoist, and that changes what you can do with a dump station on a forest road where you cannot park a trailer.
The low-profile inlet is the sleeper feature. Lots of small trailers and older Class B vans have dump valves mounted close to the ground, and a tall tank simply will not line up with them. This one is 18.5 by 10.5 by 30.62 inches in polypropylene, and owners with low-mounted valves say it is the tank that finally made their rig workable.
It comes fully assembled with caps for the hose opening and the vent, and the two wheels roll it across campground ground without any fuss. Sealing is good, which matters more than it sounds, because a leaking fitting means sewage in the storage bay of a small trailer.
Here is the honest trade. Twelve gallons is not much. A single person can fill it in a couple of days, so you are making several trips to a dump station or storing it near one. That is fine for a weekend dry camping trip or a trailer that lives within a few miles of a sewer, and it is a poor fit for a two-week plan in the backcountry.
Why small rigs need the small tank
Storage. A 21-gallon Rhino is 40 inches in its largest dimension and a Barker 42 is 45 inches. On a teardrop trailer, a small Class B van, or a truck camper you simply do not have that space, so a tank you cannot stow is a tank you will not use. This one tucks under a camper.
The 4.2 average rating is the second-lowest here, and the reason is mostly about what is missing rather than what is wrong. There is no hose in the box even though some listing imagery suggests otherwise, and there is no overfill indicator, so you need to watch the level carefully or buy a tank fill gauge.
What owners complain about
The 1-star share is 10 percent here, second only to the RecPro, and the complaints cluster on wheels popping off in transit and the missing hose. Owners also note that the printed instructions cover the larger SmartTote2 models rather than this 12-gallon unit, so expect to work out the fill procedure yourself.
My advice is simple: if you buy this, buy a sewer hose and a tank fill gauge at the same time, and check that the wheels are seated on the axle before you roll it across loose ground. With those two additions it does exactly what a small rig needs.
5. VINGLI 10 Gal Tote Tank – Best Lightweight Grey Water and Water Hauler
VINGLI 10 Gallon Tote Tank| Portable Wheeled Fresh Water Tank for Camping/Picnic/Camper/RV, Food Grade Safety & Lightweight & Durable
10 gallon
9.3 lb empty
Food grade HDPE
Two large wheels
14.76 x 9.06 x 31.5 inch
Pros
- Lightest empty weight in the roundup at 9.3 lb
- Slim profile uses less storage space than most totes
- Large diameter outlet fills and drains quickly
- Anti-sticky interior rinses out easily
- Integrated compartment stores hose and tap
Cons
- No standard 3/4 inch hose connection so an adapter is needed
- Some caps lack gaskets and plastic threads strip if overtightened
- Handle shown in listing is not included
- One report of a leak at the orange tube
The VINGLI is not a black water tote in the way the others are, and treating it as one is how people end up unhappy. It is a 25-liter wheeled hauler in food-grade number 2 HDPE, which means the same unit can move grey water from a rig, carry a backup water supply, or haul anything liquid around a campsite. At 9.3 pounds empty it is by far the easiest thing here to lift and store.
The slim profile is the reason to buy it. At 14.76 by 9.06 by 31.5 inches it is narrower than the SmartTote2 and takes up a fraction of the space of a 30 or 42 gallon tank. The two large wheels roll it over uneven ground better than smaller casters would, and the large diameter outlet moves liquid faster than the narrow bore on a typical RV tote.
Owners rate the anti-sticky interior as easy to rinse, and there is a built-in compartment under the lid for the hose and tap accessories so the small parts do not disappear. It arrives ready to use with no tools required, and the 1-year manufacturer warranty is modest compared with what Camco publishes.
Where people use it: full-time RVers moving grey water from a cassette to a portable toilet arrangement, campers who want a dedicated clean-water reserve, and anyone who needs to carry liquid somewhere a hose will not reach.
What this tank does better than the big ones
Three things. It is light enough to carry loaded with one hand on the handle, it stores in a fraction of the space, and it rinses clean fast. For a small trailer that does most of its camping near developed sites, those three things matter more than gallons.
It is also the only tank here that works as a legitimate fresh water container, since the material is food-grade. That is useful for carrying drinking water from a town stop back to camp.
What it does not do
There is no standard 3/4-inch hose connection, so you will need to make or buy an adapter before you can hook it to a sewer hose. That is extra work and the main reason people do not use it for black water.
Quality control is uneven at this tier. Some caps arrive without gaskets, and reviewers warn that the plastic threads strip if you overtighten them. There is also a report of a leak at the orange tube and weak wheels under full load, and the extended handle shown in the listing photos is not part of the package. Treat it as a utility hauler rather than a primary sewage tote.
6. Thetford 40510 Smart 18 Gallon – Best Self-Contained Portable Waste Tank
Thetford (40510) Smart Portable Waste Tote Tank with 4 Wheels – 18 Gallon Capacity
18 gallon
Four wheels
Self-storing sewer hose
AutoStop fill shutoff
Compact storage
Pros
- Sewer hose stores on the tank so nothing else must be bought
- AutoStop fill shutoff helps prevent spills and overfilling
- Four-wheel base stays stable when loaded
- Patented hose handling keeps connections clean
- Designed for compact storage between trips
Cons
- 18 gallon capacity is modest for long trips
- Costs more than bare-bones tote tanks
- AutoStop shutoff can slow filling on some setups
The 40510 is the tank you buy when you do not want to think about accessories. The patented self-storing sewer hose stays connected at the bottom of the tank, so it is always there when you need it and never a separate bag you left in the truck. Combined with the AutoStop fill shutoff valve, it removes the two things that go wrong most often: a missing hose and a spill during filling.
Four wheels give it a stable base and make it easy to maneuver when loaded, which is not something you can say for the two-wheel designs. The 18-gallon capacity sits in a useful middle spot for a couple or a small family on a week-long trip. It is also the model owners point to when they want a tank that lives in a compartment between uses rather than hanging off a ladder.
The design intent is sanitation as much as capacity. Keeping the hose permanently connected means the dirty end never sits loose in a storage bay, and the AutoStop valve cuts the flow when the tank is full rather than relying on you to watch a clear elbow and hope. That single feature has prevented more overflow disasters than anything else in this category.
The honest limitation is that 18 gallons is a modest number. Compared with the 36 and 42-gallon tanks, you are trading range for convenience, and the AutoStop can slow filling on some hose setups, so budget a few extra minutes per fill.
Who should pay for the self-contained design
New owners. If you have never used a tote, the failure mode is a shopping error, not a product error, and this tank removes most of the shopping. It is also right for anyone who stores a trailer between trips, where a loose sewer hose in a wet compartment is a problem waiting to happen.
It is a reasonable choice for a couple boondocking a week at a time, where one full tank per trip is enough and convenience beats capacity.
What you give up
Capacity and, in most cases, value. Owners note it costs more relative to bare-bones totes of similar size, and 18 gallons means several dump station runs on a longer trip. The fill rate is also slower on some configurations because the shutoff valve restricts flow.
One more thing to check: the listed weight figure on this listing is clearly wrong, showing 0.27 g. Owners treat it as an 18-gallon, four-wheel unit, so use the capacity and wheel count as the spec and confirm the physical weight for yourself if lifting matters to your setup.
7. RecPro 36 Gallon – Best High-Capacity No-Flat Tote
RecPro RV Portable Waste Tank | 36 Gallon | Blue | No-Flat Tires
36 gallon
54.9 lb empty
Non-pneumatic no-flat tires
Large ports
44.5 x 24.75 x 15 inch
Pros
- 36 gallon capacity cuts the number of dump station trips
- Non-pneumatic diamond tread tires roll over rough ground without flats
- Large ports make filling and emptying faster with less spilling
- Arrives pre-assembled and ready to use
- Bright blue finish is easy to spot at a crowded site
Cons
- Heavy empty weight of 54.9 lb adds to a large loaded total
- Lowest average rating among the large capacity options
- Basic construction compared with self-contained models
The RecPro 36 does one thing well: it holds a lot, it rolls over bad ground, and it does not need air in its tires. The non-pneumatic diamond-pattern tread wheels are the reason to consider it over the Barker 42 if you camp on gravel, sand, or desert wash. There is no tire pressure to check and no flat to change 20 miles from a dump station.
At 36 gallons it sits in the range where most family rigs can empty their holding tank in one transfer, and the large ports make both filling and draining faster with less spilling. It arrives pre-assembled, which is a genuine convenience on the first trip, and the bright blue body is easier to spot in a crowded campground than a grey or black tank.
Construction is heavy-duty polypropylene, at 44.5 by 24.75 by 15 inches and 54.9 pounds empty. That empty weight is high for a 36-gallon tank, and it grows to roughly 355 pounds loaded. You are rolling it, never lifting it.
It is a newer listing with a still-small review base of 116 entries. The average of 4.1 stars is the lowest among the large-capacity options here, with 13 percent of reviews at 1 star. That spread matters. The five-star share is 69 percent, so the people who like it like it a lot, and the people who do not are unhappy for reasons worth finding out before you buy.
Where the RecPro 36 wins
Fewer dump station trips, and no flats. If your boondocking happens on roads and pads that would punish a pneumatic tire, the solid tread wheels are the deciding factor. The large ports also reduce the chance of a splash during a transfer, which owners appreciate more than they expect to.
For a family of four with a 36-plus gallon black tank, this is close to a one-to-one match, and one transfer gets you back to square one.
Why we did not rank it higher
The review spread. A 13 percent one-star share on a large-capacity tank is a signal, not noise, and with 116 reviews the sample is thin enough that we cannot tell you what the failures are yet. Owners also describe the construction as basic next to self-contained models, meaning no self-storing hose and no fill shutoff.
The 54.9-pound empty weight also means a lighter 30-gallon tote can be easier to manage even if it means one more trip. If your route is smooth and you value the extra six gallons, this is a solid pick. If you will cross rough ground constantly and depend on the tank holding up, we would choose a tank with a longer review history instead.
8. Venustank 30 Gallon 2 Wheel – Best Complete Accessory Kit
Venustank 30 Gallon RV Portable Waste Tank 2 Wheel Tote Tank
30 gallon
57.5 lb empty
22 inch tow bar
Gate valves and rinser
Ladder hook storage
Pros
- 4.7 average rating with an 82 percent five-star share
- Kit includes sewer hoses rinse adapters elbows caps and a 22 inch tow bar
- Large solid rubber rear wheels roll over uneven ground
- Gate valves and integrated tank rinser for easy cleaning
- Ladder hook clamps to an RV or camper ladder
Cons
- Heaviest empty weight in the group at 57.5 lb
- Some assembly required before first use
- Smaller review pool than the established Camco and Barker models
The Venustank 30 ties the Camco Rhino 21 for the highest rating in this roundup at 4.7 stars, with 82 percent of reviews at five stars. The reason is the kit. You get a 3-foot sewer hose, a swivel bayonet hose, rinse adapters, clear elbows, storage caps, and a 22-inch tow bar in the box, which is a more complete package than anything else here and removes the accessory shopping list entirely.
The clear elbow is worth calling out on its own. Watching the flow through a transparent 90-degree fitting is the most reliable overfill protection you can buy, and many owners of tanks without one rely on a separate fill gauge instead. The gate valves and integrated tank rinser make draining and cleaning straightforward, and the blow-molded HDPE body is sun resistant and leak resistant.
It is a 2-wheel design with large solid rubber rear wheels that roll smoothly and handle uneven ground, and the ladder hook clamps onto an RV or camper ladder so it hangs out of the way when empty. Owners like being able to roll it like a suitcase or tow it behind a truck or golf cart. Overall size is 43.5 by 25.5 by 17 inches, and there is a 1-year manufacturer warranty.
Two caveats. It is the heaviest empty tank here at 57.5 pounds, which is more than some 42-gallon competitors, and some assembly is required before first use. Plan an hour with the instructions, and check that the valve threads seat properly before you rely on it.
Why a 4.7 rating still is not our first pick
Sample size. The 4.7 comes from 57 reviews. That is a genuinely happy customer base, but 57 is not the same as the 27k behind the Camco Rhino 21, and a tank that fails catastrophically tends to produce very loud reviews. We want more data before calling it the best.
Beyond the sample size, the 57.5-pound empty weight is a real handling issue. A 30-gallon tank at that weight is harder to maneuver over a gate or up a ramp than the Barker 31342 at 35 pounds, and that is where most owners will notice the difference.
What it is genuinely good at
Out of the box completeness. If you hate assembly, dislike hunting for a 4-in-1 adapter, and want a clear elbow on day one, this tank saves you an afternoon. The solid rubber wheels also mean no tire pressure checks before departure, which is one less item on a departure checklist that is already too long.
It is a good second tank for a family that already owns a primary tote, or a primary tote for a couple who dump frequently. Just verify the assembly and keep a spare valve cap on hand.
How Big a Portable Waste Tank Do You Need?
Match the tote to your RV’s black tank, then add about 25 percent for residual waste and hose volume. A 27-gallon black tank pairs well with a 30 to 36 gallon tote, because you want the tote to hold one full transfer with room to spare. Going much larger than your black tank buys you capacity you will never fill, and going smaller means two trips every time you empty.
Here is the sizing logic we use. First, find your RV’s black tank capacity. A family of four usually sits somewhere between 27 and 40 gallons. Second, add a third to a half again. Third, subtract what you will never recover: waste coats the walls, a residue stays in the sump, and your hose holds a few gallons, so a nominal 35-gallon tote behaves more like a 30-gallon tote in the field.
Fourth, check the loaded weight before you commit, because liquid weighs 8.34 pounds per gallon. A 12-gallon tote is about 110 pounds loaded, a 21-gallon is about 210, a 30-gallon is about 285, a 36-gallon is about 355, and the 42-gallon Barker is around 400. Anything past 300 pounds is a roll or a ramp job, not a lift. Owners who tracked their own black tank consumption for a week before buying consistently picked a smaller tank than they expected, because the daily rate was lower than they assumed.
Gate valve versus low drain hole
This is the spec that gets misquoted most often in this category. A gate valve is a 3-inch side-discharge valve you pull to empty, as on the Barker 4-Wheeler 42 and the Barker 31342. A low drain hole is a small port at the bottom of the tank that you tip the unit to use, as on the Camco Rhino 15 and 21 gallon models. If you want to roll the tank under a dump port and pull a handle, you need a gate valve. If you are fine lifting or tipping, a drain hole empties just as completely and costs less to manufacture.
Two wheels versus four wheels
Two wheels with a fixed axle mean you drag the opposite end sideways, which is fine on a paved or packed surface and annoying on gravel. Two wheels with swivel casters, as on the Barker 42, roll in any direction. Four wheels, as on the Thetford 40510, add stability and make a loaded tank far less likely to tip when you stop. Our rule: anything over 25 gallons gets four wheels or a tow handle, because a single-person mishap with 285 pounds is a back injury.
No-flat solid wheels versus pneumatic tires
No-flat wheels, as on the Camco Rhino 21, the Venustank 30, and the RecPro 36, will never go flat and need no pressure checks. They ride a little harsher on rubble. Pneumatic tires, as on the Barker 4-Wheeler 42, roll more smoothly over rough ground and absorb impact on the tank, but they crack with UV exposure and age, and reviewers report that replacing them is awkward. If you boondock on maintained gravel or pavement, choose no-flat. If you cross washboard desert roads regularly and check your tires each season, pneumatic is worth the maintenance.
Black water versus grey water
Technically any of these can hold either, and a single tank is simpler to own. Practically, owners who separate them say the grey-only tank stays in service far longer between deep cleanings, since grey water is shower and sink water rather than sewage. If your rig is a weekend camper, one tank is enough. If you run two adults on a two-week trip, a dedicated grey tank and a black tank is the setup that will not make you regret boondocking.
How to Fill, Dump and Maintain a Portable Waste Tank
Fill slowly and watch the level the entire time. Position the tote below your RV waste valve, connect the short sewer hose from the RV to the tote inlet, and secure it so it cannot slip. Then open the tote vent cap, open your RV valve, and let gravity do the work. Stop at roughly 75 to 85 percent, cap everything, and confirm the hose is empty before you unhook it.
Open the vent cap before you fill and again before you dump. This is the single most repeated real-world mistake in this category, and it is worth its own callout. A sealed tank cannot drain properly. You will get slow flow, air locks, and worst of all, sewer gas blowing back at you when the vacuum pulls. Open the vent first, drain second.
At the dump station, back the tote under the port, open the vent, and either pull the gate valve or tip the tank to the low drain hole. Let it run until the flow slows to a trickle, then close up. A clear 90-degree elbow in the outlet makes this whole step visible, and a tank fill gauge on the inlet is the cheapest insurance against the overfill that ends a boondock early.
Rinse before you close it. A short non-potable rinse hose, some holding tank treatment, and two minutes of circulating water keeps the interior from developing the smell that makes owners abandon their tote. Store it with the vent cap off and the hose disconnected, or with the hose permanently attached as on the Thetford 40510 if you prefer that. A ladder hook, a truck bed, or a strap on the RV’s rear ladder keeps it from wandering.
And if you tow the tank, strap the hitch handle to the ball. Owners report the handle unclipping on downhill grades without one. Keeping your rig’s other systems in shape matters too, so our guides to the best RV carports and the best RV TVs cover the long-term setup side of things.
Owner-Reported Problems Worth Knowing About
We would rather tell you the failure modes up front than let you find them at a dump station. These are the problems owners actually describe in reviews, and the sample sizes are what they are, so treat them as signals rather than statistics.
Small front swivel wheels jamming in rocks and ruts comes up repeatedly on four-wheel models. The Rhino 21 handle being uncomfortable to grip when full is the most consistent complaint on the highest-rated tank in the roundup. The Barker 4-Wheeler pneumatic tires cracking with age, the Barker 31342 wheel end caps and axle nuts failing during towing, and the Thetford SmartTote2 12 wheels popping off in transit are all specific, fixable parts failures rather than tank failures.
Overfilling is the most common user error rather than a defect, and the fix is mechanical: a fill gauge on the inlet, a clear elbow on the outlet, or the Thetford AutoStop valve. Plastic hose fittings are worth watching in freezing boondocking climates, where owners report splits at low temperatures. Draining slowly at the dump station is nearly always a closed vent cap.
The pattern worth noticing: almost none of these complaints are about the tank body failing. The tanks hold. The hardware around them is what gives out, and most of that hardware is replaceable with a cheap part and a wrench if you carry the right one.
Frequently Asked Questions
What is the best portable RV waste tank?
For most boondockers the Camco Rhino 21-gallon tote is the best overall pick, with no-flat wheels, a complete accessory kit and the largest review base in the category. The Barker 4-Wheeler 42-gallon is the better choice if you need maximum capacity and plan to tow the tank over rough ground, and the Thetford SmartTote2 12-gallon wins for small rigs that cannot store a 40-inch tank.
What size portable waste tank do I need for boondocking?
Match the tote to your RV black tank and add about 25 percent. A 27-gallon black tank pairs with a 30 to 36 gallon tote so one transfer empties it completely. Remember that a nominal rating overstates usable capacity because waste coats the walls and a residue stays in the bottom, so a 35-gallon tote behaves more like a 30-gallon one.
Do Camco Rhino tanks have gate valves on every size?
No. The Camco Rhino 15-gallon and 21-gallon versions use a low drain hole at the bottom of the tank rather than a 3-inch side gate valve, so you tip the tank to empty it instead of rolling it under a dump port and pulling a handle. The larger Rhino sizes in the line use a side valve. Check the specific model before planning how you will drain it.
How much does a full portable waste tank weigh?
Liquid weighs 8.34 pounds per gallon, so a full 21-gallon tote runs about 210 pounds and a full 42-gallon tote runs about 400 pounds before you count the empty tank weight. Anything over 300 pounds should be rolled or ramped, never lifted. A 12-gallon tote at roughly 110 pounds loaded is the largest that most people can lift into a truck bed by hand.
Can I use one tote for both black and grey water?
Yes, any of these tanks can hold either, and a single tank is simpler to own. Owners who keep them separate say a grey-only tank stays in service longer between deep cleanings, which is useful on long trips. For weekend camping one tank is plenty. For two adults boondocking for two weeks, separate tanks reduce how often you have to handle a full sewage load.
Why does my portable waste tank drain slowly at the dump station?
The most common cause is a closed vent cap. A sealed tote cannot drain because a partial vacuum builds inside, so open the vent cap before you open the drain valve or pull the gate. Other causes include a partially blocked inlet screen and a drain valve that has not been fully opened. A clear 90-degree outlet elbow lets you see the flow and catch a slow drain immediately.
Bottom Line on Portable Waste Tanks for RV Boondocking in 2026
The Camco Rhino 21-gallon is our pick for the best portable waste tanks for RV boondocking, because it balances capacity, loaded weight, wheel quality, and a complete accessory kit better than anything else we tested. Go to the Barker 4-Wheeler 42 if you want one transfer per empty and plan to tow across rough ground, and drop to the Thetford SmartTote2 12 if your trailer is too small to store anything larger.
Match the tote to your black tank, add a quarter for residual waste, and open the vent cap before you fill and before you dump. Get one of our other field-tested guides for the best turtle tanks while you are planning the rig, and go find your site.