Portable RV Waste Tank Review: Problems, Repairs & the Solution That Finally Worked

When we started full-time RVing, one of the questions we had to answer was pretty basic: What do you do when your holding tanks are full, but your campsite doesn’t have a sewer hookup?

Fresh water wasn’t much of a problem. We had installed a 47-gallon fresh water tank in the back of our truck so we could bring water to the trailer.

Gray water wasn’t our biggest concern either.

But there’s one holding tank that doesn’t conveniently stop filling just because you don’t have a sewer connection.

The black tank.

That’s why, in August 2019, we bought a 36-gallon Camco Rhino portable RV waste tank.

At first, we thought we’d found the perfect solution.

Several years, multiple wheel failures, homemade repairs and a macerator pump later, we’ve learned quite a bit about portable RV waste tanks.

Here’s what happened.

Why We Bought a Portable RV Waste Tank

Before we started traveling, I wanted a portable waste tank. Ed wasn’t convinced we needed one.

Instead, we installed two 47-gallon polypropylene tanks in the bed of our truck. One was intended for fresh water and the other for gray water.

Once we actually started camping, the problem became obvious. At campgrounds with water and electric hookups—or sometimes electric only—we could stay comfortably until one of our waste tanks filled.

Then we had a problem. Packing up the entire trailer just to tow it to a dump station wasn’t something we wanted to do every few days.

So we bought the portable waste tank. And Ed eventually admitted I might have been right about that one.

Why We Chose the 36-Gallon Camco Rhino

Our trailer has two gray tanks and one black tank, each holding around 30 gallons. That made capacity important.

We didn’t want a portable tank that was smaller than the RV holding tank we were trying to empty. With a 36-gallon capacity, the Rhino gave us enough room to empty one tank without worrying that we’d overflow the portable tank.

The other big selling point was the wheels. I’d read reviews of smaller portable waste tanks with little wheels that broke or fell off.

The Rhino looked substantially stronger. It had big, heavy-duty wheels, and we thought paying more for the better system would save us trouble later.

Initially, it seemed like we’d made the right decision.

Our First Impressions Were Excellent

Our first experiences with the tank were good enough that Ed enthusiastically recommended it.

The capacity was right. The tank did its job. The large wheels seemed sturdy. We could attach it to the vehicle and take the waste to the dump station without moving our entire trailer.

We even bought a mounting bracket so we could carry the empty tank on the back of the RV rather than sacrificing space in the truck bed.

It solved the problem we’d bought it to solve. There was just one complication with our particular setup.

The Tank Inlet Was Higher Than Our RV Outlet

Because we’d chosen the larger tank, the waste inlet on the portable tank sat higher than the waste outlet on our trailer. Gravity wasn’t exactly on our side.

At first, this looked like a serious problem. The solution turned out to be surprisingly simple. We used a longer sewer hose so the portable tank could sit farther away from the trailer. As the RV tank emptied, we could gradually lift sections of the hose and work the remaining liquid toward the portable tank. It wasn’t elegant, but it worked.

Once we figured out the technique, that wasn’t really a problem anymore. Unfortunately, the wheels were about to become one.

The First Wheel Failure

We had specifically chosen this tank partly because we’d read about wheel failures on other portable waste tanks. The Rhino was supposed to be the heavy-duty option.

Then, on approximately the fourth time we used it, one of the wheels came off. Ed was only towing the tank at around five miles per hour.

When he returned to the trailer, he discovered that the axle had shifted by roughly two inches and the wheel assembly had come apart.

Fortunately, we managed to find the wheel, bearings, washer and cap.

Ed reassembled everything.

But we could also see that the axle itself was moving back and forth.

Something clearly wasn’t right.

The Desert Repair Begins

When you’re RVing, sometimes you fix things with whatever you have.

Our immediate solution involved Gorilla Tape.

Ed used it to try to prevent the axle from sliding until we could come up with something better.

Further inspection showed another problem.

Parts of the plastic supporting the wheel assembly had failed. There simply wasn’t enough support in some areas, allowing the plastic to flex under the load.

And that load is considerable.

A 36-gallon tank filled with wastewater can weigh close to 300 pounds.

That’s an enormous amount of weight to put on a portable plastic tank and its wheel assembly.

Building a Better Axle

Since the original setup had failed, Ed started looking for a way to strengthen it.

We were in Quartzsite at the time, so finding exactly what we needed involved searching locally and eventually making a trip into California for steel rod that could work as a replacement axle.

And because we were living in the desert, we didn’t exactly have a fully equipped machine shop handy.

Ed and I took turns manually sawing through a roughly 5/8-inch steel rod.

That was fun.

Slow, but effective.

The idea was to replace the original axle arrangement with a solid shaft running all the way through.

We also used JB Weld and other materials to control the axle’s side-to-side movement and prevent the wheels from rubbing against the tank.

It was very much a campground engineering project.

And it worked—for a while.

Then the Replacement Wheels Failed

We tried replacement red wheels.

Those lasted approximately three months.

Then one of the tack welds holding the center bearing section to the rest of the wheel failed.

So once again, we went looking for another solution.

Next we found no-flat solid rubber wheels.

These looked much better than anything we’d tried previously.

And to be fair, they lasted considerably longer.

They carried us through the remainder of our first season in Quartzsite.

We didn’t need the portable waste tank much while we were traveling that summer, but when we returned to Quartzsite in the fall of 2020, we started using it again.

The no-flat wheels made it through our entire second season—about five and a half months.

Then we noticed that they, too, were beginning to separate.

Back to the drawing board.

The Problem With a 36-Gallon Portable Waste Tank

After living around thousands of RVers in Quartzsite, we realized we weren’t the only people improvising solutions.

We’ve seen plenty of the same large portable tanks.

We’ve also seen replacement wheels on them.

We’ve seen them carried in truck beds.

And we’ve seen large portable waste tanks being towed down desert roads with broken wheels scattered nearby and a rather unfortunate trail behind them.

That’s not something anyone wants to experience.

The fundamental problem is weight.

Thirty-six gallons of liquid is heavy.

Add the weight of the tank itself, then ask a set of relatively small wheels to carry that load over uneven campground roads or desert terrain.

Something has to absorb all that stress.

In our experience, the wheels and their supporting components became the weak point.

What About Smaller Portable Waste Tanks?

We’ve also seen many RVers using smaller 20- to 25-gallon portable tanks.

Some carry them in truck beds and use macerator pumps.

We’ve seen others carried on the back of side-by-sides.

Some RVers have built small trailers specifically for their portable waste tanks.

We’ve even seen people strap them to heavy-duty appliance dollies and tow the entire setup behind a vehicle.

And, of course, we’ve seen smaller tanks being towed exactly as their manufacturers intended.

Do those smaller tanks hold up better?

We can’t say from personal experience.

We don’t know how old those tanks are, how often they’re used or whether their owners have experienced failures.

We can only tell you what we’ve experienced with ours.

The Solution That Finally Worked for Us

Eventually, we decided to stop towing our 36-gallon waste tank altogether.

Instead, we bought an RV macerator pump.

Ours cost about $233 at the time, so this wasn’t an inexpensive solution.

But it completely changed how we use the portable tank.

The macerator connects directly to the waste outlet on the RV and pumps the contents through a standard 5/8-inch garden hose.

Needless to say, that hose is now dedicated exclusively to this job.

Before we begin, we place the empty portable waste tank in the bed of our truck near the tailgate.

The hose runs from the macerator pump to the portable tank.

Then we pump the waste directly into it.

When we’re finished, the tank is already sitting in the truck.

We drive the truck to the dump station, empty the tank and return to camp.

No towing the waste tank on its wheels at all.

For us, that has been a much better system.

Why We Still Like the Tank

After everything that went wrong, you might expect us to say buying the portable waste tank was a mistake.

We don’t feel that way.

The tank itself still solves an important problem.

Without it, our alternative would be packing up the entire trailer and towing it to a dump station every time our holding tanks filled.

When you’re settled into a campsite, that’s a lot of work just to empty a tank.

Our problem wasn’t the idea of a portable waste tank.

It was relying on the wheels to transport nearly 300 pounds of tank and wastewater.

By combining the large tank with a macerator pump and carrying the tank in the truck bed, we’ve kept the part that works for us while eliminating the part that repeatedly caused trouble.

Large vs. Small Portable RV Waste Tanks

There are advantages and disadvantages to both sizes.

Large 36-Gallon Tank

The biggest advantage is capacity.

Because ours holds more than our individual RV holding tanks, we don’t have to stop halfway through emptying one.

That’s especially convenient with a black tank.

The downside is weight.

Once a 36-gallon tank is full, moving it becomes a serious job. The wheels, axle and other components are carrying a tremendous load.

Smaller 20- to 25-Gallon Tank

A smaller tank weighs considerably less when full and may be easier to handle.

However, if your RV holding tank is larger than the portable tank, you need to pay very close attention while transferring waste.

You may also need more than one trip to the dump station.

For us, the larger capacity still makes sense.

We simply no longer depend on its wheels.

A Few Things We Learned About Towing a Portable Waste Tank

When we were still towing ours, there were several things worth knowing.

First, you can’t back up normally with the tank attached behind the vehicle. It wants to pivot rather than track backward.

Second, speed matters.

We always towed ours very slowly. This isn’t something you want bouncing down a campground road behind you.

Third, understand just how heavy your tank will be when it’s full.

Water weighs a little over eight pounds per gallon. Wastewater isn’t magically lighter.

A large tote can become an extremely heavy piece of equipment very quickly.

And finally, inspect the wheels, axle and mounting points regularly.

Our first failure happened after only a handful of uses.

Would We Buy a Portable RV Waste Tank Again?

Yes—with some qualifications.

We absolutely appreciate having the ability to empty our RV holding tanks without breaking camp.

For anyone who frequently camps without sewer hookups, a portable waste tank can make longer stays much easier.

But after our experience, we wouldn’t want to routinely tow a large 36-gallon tank on its original wheels.

Our preference is the system we use now:

RV holding tank → macerator pump → dedicated hose → portable waste tank in truck bed → dump station.

It requires more equipment and costs more initially, but it eliminates the wheel problem that caused us so much frustration.

Our Portable Waste Tank Timeline

Looking back, our experience went something like this:

August 2019: Bought the 36-gallon Camco Rhino portable waste tank.

First few uses: We loved it and thought the heavy-duty wheels justified buying the more expensive model.

Around the fourth use: A wheel came off and the axle shifted.

First repair: Reassembled the wheel and temporarily stabilized the axle.

Next modification: Reworked the axle and attempted to strengthen the wheel system.

Replacement red wheels: Lasted roughly three months before a tack weld failed.

No-flat solid rubber wheels: Worked much better and lasted through a full Quartzsite season before beginning to separate.

Final solution: Stopped towing the tank and began using a macerator pump to fill it while it sits in the truck bed.

That’s a lot more information than we had when we originally stood in the store trying to decide which portable waste tank to buy.

Hopefully our experience saves someone else a little frustration.

The Bottom Line

A portable RV waste tank has been extremely useful for the way we camp.

Our 36-gallon tank gives us enough capacity to empty one of our RV holding tanks without moving the trailer, which is exactly why we bought it.

But the wheel system did not hold up for us.

We repaired it.

We modified it.

We replaced wheels.

We replaced them again.

Eventually, instead of continuing to fight the same problem, we changed the way we used the tank.

Adding a macerator pump and carrying the filled tank in the truck bed turned out to be the solution that made the most sense for us.

So yes, after all of that, we still don’t regret buying the portable waste tank.

We just wish we’d known from the beginning that its wheels were going to take us on almost as much of an adventure as the RV.

We’ll see you down the road…and Over the Hills!

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