Trelino Evo S Composting Portable Toilet Review
camping toilet for base camp, overlanding, or to pack in your car, truck, or camper van
Home > Gear Reviews > Camping
April 22nd, 2024
Our Verdict
The Trelino Evo S Portable Composting Toilet is a simple and effective way to bring a toilet with you to most places. It’s not small enough for backpacking, but it is small enough to carry to a base camp or pack in your car, truck, or camper van. It’s also a great option for boat users and other off-grid settings without running water.
It requires no water or chemicals to use. And it separates pee and poo, which keeps the smell to a minimum. It has separate solids and liquid containers, and each container has its own tight-fitting, spill-proof lid. The solids container uses compostable collection bags that are durable and don’t leak. While you’ll have a hard time finding a place to compost human waste, these bags will break down much faster than traditional plastic bags.
I’ve been testing a Trelino Evo S Portable Composting Toilet for three months in my converted GMC Savana camper van. I’ve used this toilet in Arizona, Colorado, New Mexico, Oklahoma, Arkansas, and Illinois while camping everywhere from National Forests and BLM land to rest areas along the highway during heavy rain. In that time, I’ve gone from portable-toilet skeptical to a full-on believer. This little portable toilet easily stores in a cabinet in my van, doesn’t stink, and is ready whenever I need it.
Keep reading if you want to find out more about the Trelino Evo S Composting Portable Toilet. You can also see how many many euphemisms for pooping I can fit into one article. Spoiler alert: there are a lot of those here!
Specs
Weight: 8.6 lbs
Width: 13"
Depth: 15.4"
Height: 11.7"
Liquids container volume: 1.2 gallons
Solids container volume: 1.6 gallons
We create reader-supported, objective gear reviews independently selected by our editors. This story may contain affiliate links, which help fund our website. When you click on the links to purchase gear, we may get a commission — without costing you an extra cent. Thank you for supporting our work and mission of outdoor coverage for every body! Learn more.
Best For
The Trelino Evo S Composting Toilet is best for camping in high-use areas and other places where you can’t or shouldn’t dig a cathole to do your business. It’s also great for road-tripping, low-impact car camping in fragile ecosystems, and anywhere else you need a toilet.
What We Liked
Chemical free
Portable
Doesn’t smell
Separates solids and liquids
Secure lids for waste containers
Easy to clean
What Could Be Better
Difficult to compost human waste (many municipalities will not accept it)
Our poop jokes
How a Portable Composting Toilet Works
Most portable composting toilets, including the Trelino Evo, work similarly. If you’ve ever used a composting toilet in the backcountry or somewhere else without running water, then how a portable composting toilet works will sound familiar.
The Trelino Evo S composting toilet consists of three boxes: one main box and two inner containers that fit within the main box. When you look at this unit from the outside, you see the main box with a lid. There is a toilet seat below that lid. Inside the main box are two other containers: one for solids and one for liquids. The inner containers, which look like Tupperware, sit in the main box below the toilet seat.
To recap, there’s one big box with a toilet seat you sit on and a lid, and two smaller boxes that look like Tupperware with their own lids. Both of these inner containers can be removed from the main box independently of each other.
The toilet seat has two openings inside the ring: one funnel near the front that diverts urine into the liquids container and a larger opening in the back above the container for solid waste. This design automatically separates #1 and #2 and diverts them into their intended containers.
Before doing your business, you remove the lid from the container that holds your poop and put a compostable bag into that container. You then put a small amount of litter down. After you go, you simply put another handful or two of litter on the top to absorb odor and moisture, then snap the lid back onto the solid waste container.
For litter, you can use small animal litter (wood chips or other natural materials you’d use to line a rabbit cage, purchased separately from a pet store), wood shavings, sawdust, coconut coir, or dried coffee grounds. I save my coffee grounds after I use them, then mix them with small animal litter, which works well to cover the poo smell when you open the lid. The litter itself also helps to keep the smell to a minimum by absorbing moisture, which leads to stink.
When your solids container is full, usually after 5-8 sessions with the Trelino Evo S, you remove the bag from the container, tie it securely shut, and dispose of it in the trash or a toilet (Yes, you read that correctly: 5+ dumps hanging out in a toilet that you can’t smell. That’s what the litter, coffee grounds, and lid are for).
You can also compost it, but it’s going to be difficult to find a place that will compost human waste. Most people throw away dog poop and diapers, so throwing away your bag full of human poop isn’t that different. But make sure you’re following local laws when you dispose of that poop bag.
If you have access to a composting toilet at home, you can also empty the bag into that, then throw out the bag. Of course, you can simply empty the bag into a flush toilet, but depending on how full it is you might need a few flushes. Or, you can try composting in your home compost pile—make your own midden!
The liquids container is slightly less complicated. If you’re only going #1, after doing your business, you leave the urine in the container until it’s full or you’re in a place to empty it. You can dump your urine in a toilet and flush it away or sprinkle it around outside.
If you’re dumping your urine outside, it’s best to dilute it, or at least not dump a whole gallon of pee in one spot. That much pee could be too much nitrogen for one plant and lead to root damage or inability to flower and fruit. It will also reek of urine wherever you dump that entire gallon, especially in drier environments. And if you’re camping in one spot for days at a time, that smell will build to an unpleasant level.
Features
Materials and water resistance
The Trelino Evo Composting Toilet is made of durable plastic materials. The ABS plastic (acrylonitrile butadiene styrene) exterior is water resistant, so you can use it in the shower or hose it off to clean. It will also prevent anything that leaks out of the interior containers from leaking all over if those interior containers do leak.
The liquid and solids containers are made of polypropylene, another strong and waterproof plastic.
Soft close lid
It has a soft-close lid, so it doesn’t slam when you close it. This helps prevent your fingers from getting pinched when you close the lid.
Independent canisters
The Trelino Evo has two separate waste canisters, one for liquid and one for solid. The seat is designed to divert your pee and poo into these separate containers using gravity for #2 and a built-in funnel for #1. Both containers have lids to make removing them to dispose of waste and cleaning easier. The lids also keep smells inside the canisters.
Leakage safety
The urine container has two different screw-top lids. It has one lid with a hole and rubber membrane closure, which you use while doing your business. The other lid is a solid screw-top so you can transport your pee without spills.
The solids container uses a snap-on lid that secures tightly in place. It’s difficult to get this lid on or off, which is a good thing because it might otherwise come off on a bumpy road. That could lead to a messy situation, to say the least. Frankly, a lid that isn’t as tight as this one would be downright shitty. In emergency situations, the lid isn’t too difficult to remove, though. It’s about as difficult to remove as a tight-fitting Tupperware lid—nothing crazy, but tight enough to avoid spills.
No water or chemicals required
The Trelino Evo doesn’t use any water or chemicals. Some portable toilets, such as puck toilets, use chemicals to break down waste and neutralize odors. These chemicals have their own odors, so they still don’t smell good.
Other portable toilets, such as one you’d find in an RV, require water and a sewer hook-up. Needing a water hookup isn’t very portable at all. The Trelino Evo doesn’t require any chemicals or water to use. You should wash your hands when you’re done, and that requires water, but you can also use hand sanitizer.
Biodegradable bags
The Trelino Evo uses biodegradable bags for solid waste collection. The ones designed by Trelino for this toilet are strong and tear-resistant, too, fortunately. Because they're biodegradable, you can technically compost these bags with your poo, or they’ll at least break down faster than plastic in a landfill.
Every Trelino toilet comes with 10 of these bags to get you started. That’s 50+ trips to the land of no catholes or wag bags! After that, you can purchase more 2.6-gallon biodegradable bags from Trelino or elsewhere, but be sure any bag you use is thick and tear-resistant. There are very thin 2.6-gallon compostable bags available that are designed to line a countertop compost bin and hold food scraps. Don’t use any of those thin green bags in your Trelino Evo! You wouldn’t want that bag to tear.
Litter material
Litter material should be carbon-rich, absorbent, lightweight, and have the ability to deodorize. The most common litter materials that most people use are small animal litter, sawdust, wood shavings, coconut coir, organic peat moss, soil, or dried coffee grounds.
As I stated above, I use a combination of small animal litter I bought from a pet store with dried coffee grounds. This combination absorbs moisture well and neutralizes the poop smell.
Performance
Setup
The Trelino Evo requires very little setup. It comes with the solids and liquids containers where they should be for collecting #1 and #2, so it’s almost ready for use immediately. Once you pick where you’re going to use this portable, place it on the ground, lift the seat, place a collection bag in the solids container, replace the seat, and…go!
Functionality and ease of use
The Trelino Evo is very easy to use. Once you’ve set up your portable toilet in the perfect spot, with the best view and enough privacy, using it is as easy as any other toilet. It automatically separates #1 and #2, and there is no flushing required.
When you’re finished, if you went #2, place a handful of litter in the solids container and secure the lid on top. Place the rubber stopper in the pee funnel’s opening. Then, simply close the lid.
Compared to other portable toilets I’ve used, such as wag bags or the simple bucket with a toilet seat we’ve used on river trips (a groover), the Trelino is very easy to use. The other types of portable toilets we’ve used require a difficult dance, where you pee in one place and then waddle back over to poop. The Trelino has separate containers for liquids and solids and separates them for you, so you don’t have to do that dance.
Capacity
The Trelino Evo S has the capacity for one person to use it for about a week before you’ll have to empty the solids container. In our experience, we usually run out of water or food before we run out of room for our poo in the solids container, so we're bound to head into town anyway.
The solids container is 1.6 gallons. We found this holds about 5-8 poos. We’re usually pretty liberal with the sprinkling of litter after we do the deed, so the solids container is often full after about 5 uses.
The urine canister holds 1.2 gallons. This means you get about 10 uses before you have to empty it. We empty it more frequently because the smell of pee is stronger than the poo smell. It’s also easier to disperse smaller amounts of urine.
Odor control and ventilation
We’ve been using the Trelino Evo S in a campervan for three months, and it is shockingly good at controlling odor. We were pretty skeptical at first and were worried that storing it inside our camper would be downright stinky. However, the lid on the solids container and membrane closure for the urine canister lid do a great job of preventing odors from escaping those containers.
These containers don't have ventilation, and when you open the lids, neither container smells good. But the containers don’t smell nearly as bad as that composting toilet in the woods you have to psyche yourself up for and hold your breath just to use. Since the toilet separates #1 and #2, your pee and poo don’t mix. This prevents them from creating that truly foul smell you only get from pee and poo soup (gross!). Setting it up outside helps with ventilation, too, of course. But we’ve used it indoors plenty of times and still store it inside the van. It’s surprisingly good at odor control.
User Experience
Comfort and convenience
The Trelino Evo is quite comfortable when sitting on it. The seat is smaller than a typical toilet seat, and it looks like it might be too small to easily sit on. But the smaller size doesn’t negatively affect the comfort. If you’re wider or taller, this toilet might be less comfortable, but it’s small enough that you could feasibly squat over the top if isn’t comfortable to sit on.
Stability
This little box is small enough to feel stable while you’re sitting on it but not too small to make it easy to sit on. It has a 330-pound weight limit and has always felt stable to me, a slightly smaller than average man. I’ve tried rocking from side to side to test the stability and have accidentally kicked it a few times. I’m confident this toilet won’t tip easily.
Even if you put it on uneven ground and then sit down, it doesn’t tip easily. You’re pretty low to the ground when sitting on the seat, and it’s wider than it is tall. The low center of gravity and the fact that it has a relatively wide base make this small little box toilet super stable.
Durability and reliability
The Trelino Evo S exterior material is made of durable plastic, acrylonitrile butadiene styrene, or ABS for short. This material is very durable and holds up well to the rigors of daily use. After three months of being jostled around in my van, it has a few minor scuffs, but nothing that looks like it will get worse or break. Otherwise, the exterior is still in near-perfect shape.
The even more important inner containers still look to be in great shape as well. The liquid and solids containers can be purchased separately if you want to replace them or have extras as well.
The body material is also waterproof, so it's spill-proof. The lid fits tightly onto the lower portion of the body, which keeps everything inside from getting out. Smells and liquids don’t leave this box.
The liquid and solids containers are also very durable. They have tight-fitting lids to keep their contents in place. These containers are made of polypropylene, another type of plastic that is very strong and extremely waterproof.
Maintenance requirements
The Trelino Evo S requires very little maintenance. The interior containers are easily removable, making them easy to empty and clean. I use vinegar diluted in water to clean the containers, seat, and pee funnel portion of the seat. Other than regular cleaning and emptying, you don’t have to perform any other maintenance.
Ease of cleaning
The Trelino Evo S is super easy to clean. As I mentioned above, the solid and liquid containers come out without issue. This makes cleaning them simple. I use diluted vinegar to clean the inner containers and the exterior body. I also occasionally use soap and warm water to clean the interior containers more thoroughly.
Women vs Men
There are many positive customer reviews from women on Trelino’s website for this toilet, so it seems to work just as well for women as it does for men.
So far I’m the only tester at Treeline who has used the Trelino Evo S. I’m a man, so I can’t speak to a woman’s experience on this. But based on positive customer reviews from women on Trelino’s site, “Pretty fantastic off-grid toilet for a lady!” and, “No more getting out of the van at night for this girl!” we think it works just as well for women as it does for men.
How We Tested
For the past three months, I've been testing the Trelino Evo S Portable Compost Toilet in a converted GMC Savana campervan. I’ve used it while camping in high-use dispersed camping areas in Arizona, Colorado, and New Mexico, when it was pouring rain outside at rest areas, during spring storms in the desert, and while stealth camping in Tucson and Denver.
When not actively using the Trelino, I store it in a cabinet below a bench seat in my van. Whenever I have to go, I remove it from the cabinet, lift the lid, and immediately have a comfortable and easy-to-use toilet anywhere I need it.
Other Models to Consider
Trelino Evo M
Weight: 9.5 lbs
Width: 13"
Depth: 15.4"
Height: 14"
Liquids container volume: 1.2 gallons
Solids container volume: 2.1 gallons
At 14 inches, the Trelino Evo M is slightly taller than the Evo S but otherwise has the same dimensions. This means the Evo M model has the same footprint as the Evo S, but it has room to accommodate a larger 2.1-gallon solids container. It has the same size urine canister as the Evo S. The Evo M (9.5 lbs) also weighs one pound more than the Evo S (8.6 lbs). This model is still about as portable but sits higher and has more capacity, so it’s slightly more versatile.
View the Trelino Evo M
Weight: 10.8 lbs
Width: 13"
Depth: 15.4"
Height: 16.9"
Liquids container volume: 2.6 gallons
Solids container volume: 2.6 gallons
The Evo L model is even larger than the Evo M. It is 13 inches wide, 15.4 inches deep, 16.9 inches tall, and weighs 10.8 pounds. This portable toilet has a larger footprint than the Evo S and Evo M, so it won’t fit in as many small spaces. The Evo L has larger-capacity 2.6-gallon containers for both urine and solid waste. If you’re looking for a replacement water and chemical-free toilet for your RV or for multiple people on a weekend trip, this is the highest capacity option.
Compare prices of the Trelino Evo L
Weight: 3 lbs 1 oz
Width: 13"
Depth: 14"
Height: 15.6"
Liquids and solids container volume: 5 gallons
The Reliance Luggable Loo is a bucket-style portable toilet without a urine separator. Like the Trelino models, it uses bags to collect waste, but you have to be careful not to put too much liquid in the bag and bucket. This model is not nearly as odor-resistant as the Trelino, but it is more affordable. It also doesn’t come with any bags, so you’ll have to buy those separately. See our guide to Best Human Waste Bags and Toilet Kits for more recommendations.
Compare prices of the Luggable Loo
About the Author/Why You Should Trust Us
Sam Schild has been pooping since the day he was born. He started with diapers like most of us, then he moved on to using a regular flush toilet. His mother insists he was potty-trained earlier than other kids, but we’re not convinced that’s actually true since this is coming from his mom and it’s one of a mom’s many jobs to believe their kids are truly special.
Since his potty training days, Sam has pooped in some really scenic places on backpacking, mountaineering, and bikepacking trips. Some of his most memorable pooping experiences were along the Pacific Crest Trail in the North Cascades, where there are composting toilets dug into the sides of mountains with epic views to enjoy while doing your business. He has pooped in wag bags on mountaineering trips up the Grand Teton, in the infamous backcountry toilet on Longs Peak, in pit toilets at trailheads all over the country, and in more cat holes than he can count while backpacking.
You can learn more about Sam on his author page.
