There are three main types of toilets that can be used in recreational vehicles (RVs), and choosing the right one can depend on both the available space and intended use. Most recreational vehicles use a ball valve toilet that empties directly into a sewage holding tank. If an RV has a working black water tank, this is usually the the best toilet to choose. Another option is a portable RV toilet with a tank cartridge that can be removed and dumped manually. Composting toilets are also available, and these can be the best choice for people who spend a substantial amount of time camping in areas with no access to utilities.
The most common type of RV toilet utilizes a ball valve and is designed to use very little water for each flush. Rather than holding water in a tank or bowl like regular toilets, these units only use water when flushing. The ball valve normally seals the bottom side of the bowl and is rotated during the flushing process to provide a direct conduit to a waste water tank. This is usually the best choice for any RV that has an appropriate waste tank due to ease of use and operation.
Some advanced models can mimic the action of a regular toilet more closely by automating the application of pressurized water and the opening and closing of the ball valve. These units still conserve water by only using enough to perform each flush, though they can reduce the amount of cleanup or rinse work that is needed after each use. An RV toilet like this can be more expensive than simpler designs, though they may also be more comfortable and convenient to use.
Portable RV toilets are an option that can be well suited to small camper vans and trailers. If an RV has only a single waste water tank, one way to help keep it from filling too quickly is to use a portable RV toilet that can be dumped separately. Some camper vans lack built-in bathroom facilities, in which case a portable unit can be the least expensive and simplest way of adding a toilet.
Another RV toilet option is a composting unit. These unique toilets can be quite expensive, though they are a common choice for people that like to camp in remote areas. Dry camping, or boondocking, is an activity that involves visiting wilderness or nonstandard camping areas for extended lengths of time. Since these areas lack utilities such as water or RV dumps, a composting toilet that requires little or no water and does not need to be dumped can be instrumental in extending the length of a trip.