A Guide to RV Water Tanks
One of the best things about camping in a recreational vehicle is that you get to travel with your very own kitchen and bathroom. Because you have your own facilities, you can get out in nature without having to sacrifice any creature comforts of home. But unlike your house, where water always comes out of the tap and waste goes down the drain never to be thought of again, RVs require a little bit of work to keep things flowing. That’s why RV owners need to understand the differences between the water holding tanks under their units.
There are typically three types of holding tanks in a motorhome, fifth wheel, or travel trailer that store fresh water and wastewater. Dealing with this necessary, but decidedly unglamorous part of your RV adventure can be intimidating, but these systems are designed to be easy to use. This is especially true if you’re camping in a Bowlus, where we’ve even removed the need for the dreaded “stinky slinky.”
RV Fresh Water Tanks
The first of the three types of holding tanks we’ll take a look at is the RV fresh water tank. As the name suggests, this is the tank that holds the water that comes out of your faucets in the kitchen, bathroom, and shower. Because this is your cooking and drinking water, you’ll want to be sure to fill your tank with a hose devoted just to fresh, or potable water. To keep things sanitary, take care to not let the ends of the host hit the ground as you’re hooking up or tearing down.
The Bowlus features a 19-gallon fresh water tank and has a probeless tank monitoring system so you’ll be able to quickly and accurately gauge how much fresh water you have left. Because city water pressures can be higher than the 40-60 pounds per square inch (PSI) recommended for most RV plumbing systems, every Bowlus also comes with a pressure regulator on the water inlet to prevent burst pipes and other plumbing issues.
To ensure the water in your tank is odorless and clean, it’s also a great idea to use a water filtration system. A water filter will not only improve the taste of your water, it’ll also protect your plumbing by removing sediment before it has the chance to clog things up. If your RV doesn’t come with a filter, you can buy one to attach between the spigot and the hose running to your RV. But that’s not necessary when you’re in a Bowlus Terra Firma, which comes standard with a fresh water filtration system. Our carbon filters remove bacteria, sediment, chlorine, and other chemicals from your water supply. And because you can get fresh, clean water straight from the tap, you’ll have fewer plastic water bottles to recycle.
RV Grey Water Tank
The next tank located under your RV holds the dirty or “grey” water that goes down the kitchen and bathroom sinks, as well as the shower drain. Large motorhomes, travel trailers, and fifth wheels may have two grey water tanks. To maintain the health of your unit’s plumbing, it’s best to keep a filter on the kitchen sink drain to catch any food particles. Most RVs don’t come with garbage disposals, so food scraps should be disposed of in the trash as they can lead to clogged pipes.
Proper disposal of your RV’s grey water is a consideration when boondocking or camping off-grid. In many places, including national forests, national parks, and other federal lands, it’s illegal to empty your grey water tank on the ground. It’s generally only allowed in specific areas on BLM lands. State laws vary, so you’ll need to check before dumping your grey water tank in a state park or forest.
Most boondockers avoid dumping grey water on the ground because it can be harmful to both the environment and wildlife. Grey water may have traces of food, grease, hair, as well as remnants of the soaps and cleaning products you use, which can pollute the bodies of water they reach. Also consider that releasing the 20 gallons of grey water that most RV tanks hold (Bowlus’ tanks hold 21-gallons) can cause erosion.
Before you dump your grey water into the sewer, consider that it can be reused to water your own lawn or garden. You’ll want to make sure that you use biodegradable soaps and cleaning products in your RV to reduce the number of chemicals that ultimately reach your greenery. You may also want to filter it to remove any food particles (a pair of pantyhose works well). It’s best to recycle your grey water quickly because after 24 hours it may start to smell.
RV Black Water Tank
The last of the holding tanks under your RV holds the waste from your toilet. In RVs that don’t have a grey water tank, your water waste drains into this tank as well. A blackwater tank must be emptied at either a dump station or the sewer connection at your campsite. You do this by connecting a sewer hose, or stinky slinky, to your RV and the sewer connection. To avoid clogs, you’ll want to use single-ply toilet paper. Your black water tank will also need to be sanitized with chemicals to keep odors to a minimum.
Black Tank Alternatives: Composting and Cassette Toilets
Both composting and cassette toilets are popular alternatives to black water holding tanks. Composting toilets turn human waste into, you guessed it, compost. They don’t use any water, but they’re big, expensive, and there are a lot of challenges venting out the, erm, smell.
A cassette toilet is a permanent toilet with a portable black tank. To empty the toilet waste, you simply remove the portable tank and empty it in any public restroom or at your campsite’s sewer connection. No need to hook up your rig and tow it to the dump station. Typically the size of a small suitcase, most cassette tanks come with rollers making them easy to transport. They’re widely used in Europe, and in the US are commonly found in class Bs (camper vans).
After a significant amount of research and design, we decided to install cassette toilets in all of our Bowlus models. Our hygienic, easy emptying cassettes have a 4.5-gallon capacity and there’s a warning system that tells you when it needs to be emptied. To empty the cassette, you simply pull it out from the external hatch and empty the contents into any toilet. We’ve also taken care in the design to ensure there’s no splash back.
Every Bowlus comes with our custom ventilation system, similar to the process seen in sewage treatment plants, that eliminates odor. Our high-performance ventilator creates a slight negative pressure in the cassette when the toilet valve is opened. This allows fresh air to be drawn into the system, removing any new gases from the toilet bowl and preventing odors from escaping from the tank. The process accelerates the decomposition of the tank’s contents so that chemical additives aren’t necessary. It also means that you can use your favorite brand of soft, double ply toilet paper. When you’re camping in your Bowlus, you won’t have to sacrifice a thing, not even in the bathroom!
Water tanks in travel trailers may not be glamorous, but at Bowlus we’ve created a system that is easy and convenient to use. By eliminating the black water tank and replacing it with a cassette toilet, our RVs are designed to provide you with the flexibility you need for any camping adventure.