In a marketplace as busy as the RV industry, it can be challenging to navigate. There is a growing number of products and manufacturers hitting the market each year, filling the shelves with additional options and accessories.
The same can be said of even one manufacturer who produces so many similar products that it can be difficult to comprehend their differences.
For instance, Thetford produces a vast range of portable toilets with several target markets. Therefore, this article has been constructed to give you a clear comparison between their 135 and 345 models.
Thetford toilets
Toilets are the number one necessity in a fully functional RV after a bed. They are what make the space livable for extendable periods of time. Fortunately, they have come a long way in recent years with a multitude of upgrades and refinements which make them bespoke to every style of RV adventure.
Thetford is considered the trailblazer in the RV portable toilet industry. They’re a renowned manufacturer who has expertly targeted the RV market to perfectly suit every customer’s potential needs. Although they have branched into other products, their brand has been created on the back of innovative and highly functional portable toilet systems.
Specifically, they produce a range of cassette toilets. They are compact systems operating with a small clean water reservoir and a separate chemically primed waste water compartment. These toilets can separate so the wastewater can be emptied easily.
There are numerous potential configurations depending on the demands of the RV user. In this case, there will be a comparison between the 135 and the 345 models to see how they different.
Comparison Thetford 135 VS 345
Here is a detailed comparison of the two models of cassette toilet, the 135 and 345:
| Features | Thetford – 135 | Thetford – 345 |
| Dimensions | 12.2” X 13.5” X 15” | 13” X 15” X 16.8” |
| Fresh Water | 2.6 Gallons | 4 Gallons |
| Waste Water | 2.6 Gallons | 3.2 Gallons |
| Number of Flushes | 27 | 33 |
| Flush Style | Bellows | Piston |
| Level Indicator | No | Yes |
| Weight | 7.9 lb | 8.4 lb |
| Price | Approx $120 | Approx $140 |
1. Dimensions
Space is always in short supply in any RV. Therefore understanding the specific dimensions is an essential consideration when purchasing a toilet. The 135 is the smaller of the two by around 1-2 inches per dimension.
It is a subtle difference but substantial in confined RV spaces, particularly for those who are converting their RV out of small vans or other non-bespoke vehicles. Moreover, the size of the toilet seriously impacts the maneuverability of the cassette toilet. They are required to be moved and replaced continually.
Therefore, provisions must be made within the RV to orientate the toilet continually. When the toilet is at its capacity, it is surprising how heavy it can become. Rendering the ease of maneuverability and, by extension, its dimensions are more important than it initially appears.
2. Storage Capacity
Portable toilets operate using a two-tank storage system. They require clean flushing water to push waste through the system into the waste tank. The waste or black water tank is initially filly with a chemically primed to disintegrate and neutralize any organic material.
The capacity of these tanks is directly linked to the potential usage of the toilet. The 135 contains 2.6 gallons of fresh waste, and the 345 holds 4 gallons of fresh and 3.6 waste. As you may expect, the larger the capacity, the longer it can go without emptying and refilling.
Larger toilets like the 345 would better suit RV adventures that include families. Additionally, the larger tank would be more applicable to RV vacations which will spend a lot of time off-grid and away from standard facilities. Moreover, the fluid storage is, of course, directly connected to the overall weight of the toilet.
However, it may seem optimal to have a larger toilet if you are a family. It might be overly cumbersome to maneuver continually if you are always in campsites with easily accessible facilities. Therefore, the 135 could also be considered depending on the user’s specific requirements.
3. Number of Flushes
The flushing volume will also be closely related to longevity and volume of use. The 135 offers around 27 flushes, whereas the 345 can provide around 33. This is an interesting difference, considering the dimensional and storage comparison.
The 345 holds 1.4 gallons more fresh water, equating to 6 more flushes overall. It appears to be a very minor benefit for holding around 11lb heavier.
However, the 345 is generally larger and, by extension, utilizes a larger volume of water per flush. Arguably this is a significant disadvantage when using the larger 345 system, as you do not receive the expected benefits.
4. Flushing Operation
The most popular flushing style for portable toilets is a manual bellows system, which is used by the 135. The purpose of the system is to implement an inexpensive mechanism that can be operated with electricity at the user’s discretion. It is a concertina-style pump on the side of the unit, which pushes freshwater into the toilet basin.
The pressure build-up is enough to open the waste storage seal and empty the basin. The 345 uses a different manual flushing style, employing a piston to generate pressure. It is considered a more luxurious mechanism as it usually requires less pressure and only one push to clear the basin.
It generates pressure through a piston which can evacuate the basin far faster and reseal it to prevent any noxious odor from escaping. Typically it is the preferred flushing operation for RV owners.
5. Level Indicator
Identifying the black water tank fill level is a simple but critical component in cassette toilets. Essentially, it is an indicator that displays how filled the waste water tank is and how close it is to capacity.
On the Thetford, it is represented through a dial on the side of the unit, which grows increasingly red as it becomes full. This is a standard feature on the 345 but not on the 135. Some may find this to be a substantial negative for the 135 as you may be left in the middle of nowhere with a full toilet.
6. Weight
The empty weight of the Thetford toilets is surprisingly similar, with the 345 being only ½ a pound heavier. The actual weight comparison is made when both are filled with their required amount of water.
Bear in mind that the waste tank also contains water and chemicals in it when it is reset. Therefore it is heavier than the rating may appear. At maximum capacity, the 345 can weigh around 75lb +.
This massive load would be difficult to maneuver easily within a compact RV environment. Compared to the 135, which has a total combined weight of around 60lb. Both have a very large physical capacity considering they weigh only around 8lb when empty.
Conclusion
Both the Thetford 135 and 345 offer similar capacity and functionality. They are both regarded as high-quality and well-functioning products. However, their subtle differences can make all of the difference. The purpose of portable toilets is to be maneuverable, simple to use, and compact.
However, the 345 offers a more long-term, higher volume capacity, ideal for longer-term trips or larger groups. Although it should be noted that it is far heavier and still requires regular emptying to function optimally.
The 135 is ideal for smaller RVs, which typically have a solo occupant or couple. It is lighter and more maneuverable, but it has a poorer capacity and a less powerful flushing mechanism. Whatever the buyer’s preference, these toilets are well suited to the job they are made for.
