Key Points:

• Your rental RV’s black water holding tank stores feces and toilet paper as well as liquid waste like urine. Properly treating and caring for your black tank is very important if you want to avoid clogs and odors. 
• Your rental’s gray water tank stores lightly used water or “gray water” from your sinks and shower drains. Depending on whether you’re on full-hookups or not, the way you care for your gray tank will be different.

Renting an RV for your first RVing adventure is very exciting! But it’s understandable to be a little overwhelmed by everything to know about your rental RV, especially the wastewater system. But don’t worry, that’s why we wrote this guide! This guide will go over some of the basics of RV wastewater systems and how to use them properly. 

Note: The rental facility where you rented your RV may have given you alternative instructions. Make sure you follow their instructions so as not to cause damage to their equipment.

Your RV Black Water Holding Tank

Your rental RV has a tank under the toilet that collects the waste (feces, urine, toilet paper) from your toilet. This is called your black water holding tank. Maintaining this tank is crucial to enjoying your time in your RV. By maintaining this tank you’ll avoid nasty sewage odors seeping into your RV as well as clogs of poop and toilet paper gunking up your tank. Let’s explore what maintaining these tanks looks like.

1. Keep your black water tank valve closed unless you’re dumping your tank. It may seem counterintuitive but believe it or not, keeping your black water holding tank valve closed actually aids in clog prevention. When you leave your black water tank valve open it causes all the water to escape from the tank, leaving only solid waste inside your tank to build up and eventually cause a clog. Keeping your valve closed traps the liquids, thus helping keep the solids not so solid. 
2. Use lots and lots of water.You can do this in a couple ways: 
3. Hold down your toilet’s flush pedal for 10 seconds every time you flush. This will ensure there’s plenty of water in your black tank at all times. As mentioned earlier, water prevents solid waste from creating clogs.
4. Keep several inches of water inside the toilet bowl whenever you’re parked. This creates a water barrier to keep smells out of your living space.
5. Dump your black water tank every 3-5 days or when your RV's tank level sensors read ¾ or ⅔ full. This will help you avoid strong odors in high heat and will ensure you don’t get any clogs. Click here to learn how to dump your black water holding tank.
6. Use a high-quality waste digesting product that will liquify the poop and toilet paper in your black tank. We recommend that you use RV Digest-It Plus. 

Guide Continued Below

Gray Water Holding Tanks

Your rental RV also comes with a gray water holding tank. This tank stores the “lightly used” water (or gray water) from your sinks and showers. Again, properly caring for your gray tank will help you avoid foul odors that can develop in your grey tank when food, grease, and soap scum start to decompose. The proper steps for caring for your gray tank are very easy to follow:

1. If your gray tank is hooked up at an RV park or campground, leave your gray tank valve open, which will allow water to flow freely out of the tank.
2. If you leave your gray tank valve open, always create a dip (or “p-trap”) in the gray water hose.This will cause a temporary water barrier to form, keeping odors from creeping into your RV. It should look something like this:

3. If you aren’t hooked up at a RV park or campground, keep your gray tank valve closed.It’s usually illegal to let your gray water dispense onto public land. Be sure to check all local and state laws.
4. If you’re not hooked up at an RV park or campground, treat your gray tank with a high-quality gray tank treatment to digest the grease and soap scum in your tank and eliminate odors. We recommend RV Digest-It Plus, which also works well in both gray and black tanks.
5. Dump your gray tank when the tank level sensors read ⅔ or ¾ full.

Important note: Some states will require you to keep your RV sewer hose off the ground. Be sure to check your specific state’s rules.

Final Thoughts

Renting an RV shouldn’t be stressful, and we’re here to help make sure your first experience goes as smoothly as possible! The tips and procedures included in this article will get you started, but if you’re interested in more advanced information and treatment methods, we recommend The Unique Method. The Unique Method has helped RVers all over the country maintain clog-and-odor free wastewater systems every time they hit the road.

If you have any further questions about your RV rental, please see all of our additional resources below. You can also reach out to our customer support team. We’re happy to to help. Happy Camping!

Further Reading:

• How to Dump Your Black and Gray Tanks
• Cleaning RV Holding Tank Sensors
• How to Fix Odors