RVing can take you to some beautiful locations and help you create wonderful memories. But not every part of RVing is pretty. Maintaining and emptying your septic system on a regular basis is an unglamorous—but necessary—part of any RV adventure. And without proper maintenance and care of this system, things can get pretty ugly.
Whether you’re a new RV owner or you plan to rent an RV it’s important to know how to care for your RV tanks properly. This handy guide will help you get started.
What does an RV septic system look like?
Three main tanks located underneath the RV
Recreational vehicles typically come with three tanks located on the underside of the RV to keep things running smoothly.
1. Fresh Water Tank
As the name suggests, this tank is for fresh water. This is the water that comes out of your taps when using the water pump.
2. Grey Water Tank
The grey tank holds the dirty water from your RV shower and the kitchen and bathroom sinks. Some older trailers and vintage RVs may not have this tank.
3. Black Water Tank
This is the one that tends to scare new RVers. The black tank holds waste water from the toilet. If your RV does not have a gray tank, all dirty water is dispensed into this tank.
When not maintained properly, any one of these tanks can cause problems.
How often should I empty my RV tanks?
When they are about two-thirds full
As mentioned above, RV black and gray water tanks hold wastewater from your sinks, shower, and toilet. Tank sizes vary by RV, but you will need to empty or dump your tanks frequently when you are living in an RV. How often you will need to dump will depend on your water use and the size of your tanks.
How often you need to empty your tanks is relative. If you are traveling with a large number of people, you may need to empty your tanks every other day. If it is just you and your spouse, once or twice a week may be sufficient.
A general rule of thumb is to wait until your tanks are two-thirds to three-quarters full before emptying them. It creates a much better flow when dumping making the process more efficient.
Most RVs manufactured within the last 10 years have sensors that tell you how full your holding tanks are. This is a great way to gauge when to dump, but be warned! After a year or two, these sensors may not show an accurate reading. Even new ones may give an incorrect reading because of paper or other waste sticking to the sensor making it read full when in fact it’s not. It’s important to stay cognizant of how much water waste you are really accumulating.
You should check these sensors everyday (or a few times a day if you are using a significant amount of water) to learn how quickly your tanks are filling.
So what if you forget to check your sensors and let the tank overflow? If your gray tank is full, water will stop draining from the sink and/or shower pan and they will continue to fill with water.
If your black tank is full, the same thing happens except it is much nastier. Always dump before the sensor indicates full. Believe me you do not want to learn this lesson the hard way.
Where do I dump my RV tanks?
Dump your RV tanks at designated RV dump stations
Campgrounds and RV parks will advertise their sites as full hook-up if they have electric, water, and sewer connections. If your campsite does not have a sewer connection, you will need to find a dump station.
Many RV parks have a dump station on-site for campers to use. Some RV parks may offer a honey wagon service where they come to your campsite and dump your tanks into a mobile dump station.
If you are boondocking and need to find a dump station on the road, you can use the AllStays app to find one near your campsite or along your route. Most truck stops will charge 5 to 10 dollars to use their dump station. For everything you need to know about finding and using dump stations read How to Find and Best Practices for Using RV Dump Stations.
How do I empty my RV tanks?
Follow these steps
Before your first camping trip make sure you have a quality sewer hose and some disposable vinyl gloves to protect your hands.
Next, be sure to identify the valves on the outside of your RV. These will be clearly marked grey and black.
Connect your sewer hose to the valve on the RV. Take the other end and secure it to the sewer you are using. Ensure it is fastened on both ends before pulling the lever to open a valve!
A clear elbow is one of the most important pieces of equipment an RVer can own because it allows you to see when the water coming through your dump hose is running clear. The clear elbow can be attached to either or both ends of the sewer hose.
Always start with the black tank. Remember, the toilet waste water dumps directly into this tank. Never dump this water anywhere except designated dump stations. Dump stations are always clearly marked.
To empty, pull the valve and let the tank drain. Close the valve when you can no longer hear or see any liquid coming through the hose. Ensure the valve is closed completely. This is very important. Leaving a black tank valve open is an absolute no-no. It will cause all the liquid to flow out leaving the solids no way of draining.
When you’ve ensured the valve is shut, open the grey tank valve. Again, close when done.
Some people leave the gray tank valve open and let it drain continuously. This is NOT a good practice. Flushing the gray tank after the black tank helps flush any solids stuck in your sewer hose. If you keep this valve open, you will not have that extra water to flush out the sewer hose after dumping the black tank.
For easy clean up, go slowly when detaching the sewer hose. Many RVers use a sealed plastic container to store the sewer hose when not in use.
How do I maintain my RV septic system?
Regular dumping, flushing, cleaning, and careful usage to prevent odors, clogs, and damage
Once you get the hang of emptying the tanks on your recreational vehicle, the process can go quickly and smoothly. But there’s more to using your tanks properly than emptying them—maintenance is just as important and will help prevent trouble down the line.
In general, regular flushing along with cleaning and sanitizing your tanks will keep the system up and running fairly free of problems.
Other things to know about your RV holding tanks
Fresh water tank
Dedicated holding tank that stores potable water for drinking, cooking, and showering
The least scary of the three tanks, the fresh water tank still needs maintenance from time to time.
When hooked up to water or filling the tank, use only a potable water hose. These are easy to spot because of their white color. For more on this important topic read What Is the Difference Between a Garden Hose and an RV Drinking Water Hose?
With this tank, it’s important to pay attention to the weather. A heated RV water hose will give you safe drinking water even when temperatures dip below freezing. These hoses cost over $100 depending mostly on length but will save you a lot in frozen pipes and related issues. I have an entire article devoted to this topic: Winter RV Camping Must-Have: Heated Water Hose
If the water tank begins to smell or taste strange, it may be contaminated.
Use household bleach to clean the tank. DON’T use bleach with any added fragrances or any other special ingredients. NEVER add undiluted bleach directly to your water tank or RV water system. It can damage seals, gaskets, and fittings in the plumbing.
Dilute the bleach it in at least 1 gallon of water before adding it to the water in your fresh water tank. Pour ¼ cup of bleach for every 16 gallons of water in your tank.
Driving around for a couple of miles can slosh the sanitizing mixture around to help ensure that as much of the fresh water system as possible gets treatment. After letting the sanitizing mixture sit for six to eight hours, completely drain the fresh water tank from your low-point drain. The low-point drain is typically near one end of the fresh water tank.
Once the tank is empty, refill it with fresh water. Run your faucets one at a time until you no longer smell bleach. If you drain the tank but still smell bleach, repeat the process until the bleach smell disappears.
Gray water tank
Collects wastewater from sinks and showers
Again, this is where runoff water from your sinks and RV shower is held. In large travel trailers and fifth wheels there may be two gray tanks.
There are several ways to help keep your RV gray water tank clean. You can start before the water even turns on by minimizing any food particles that are washed down the drain in your galley (kitchen) sink. For instance, use your napkin or paper towel to wipe off your plate before washing it. Do the same with pots and pans. Any food residue that you can remove from your dishes BEFORE you wash your dishes means there’s that much less to get washed down the drain, helping to keep the gray tank cleaner.
If you’re having a problem with odor coming from your gray water tank, there are a couple of simple things to try. You want to use a solution that will break down grease and other fatty buildups that can cling to the tank walls.
I recommend using Dawn dishwasher detergent. Pour a cup into the galley sink when your gray tank has about a half tank of water before a day of driving. The detergent solution will slosh around as you drive. After setting up your rig at the new camping site, dump the gray water tank. This process will flush out whatever material you were able to break loose from the tank interior.
Black water tank
Stores waste and sewage from the toilet
The RV black water tank is basically a repository—a holding tank where waste from the toilet is sent and held until it’s convenient to dump it into a sewer.
Use a lot of water. Water! Water! Did I say water? The one place you won’t want to conserve water is inside the black water holding tank. Water helps flush everything down better and when mixed with Dawn dishwasher detergent or a holding tank treatment, water interacts with the detergent and breaks down RV toilet paper and solid waste. Before using the toilet, fill the bowl with water at least halfway. When you flush, everything should go down much easier.
There are a few good rules of thumb for minimizing trouble with the dreaded black tank:
- Use RV-friendly toilet paper (Read my complete guide to the best RV toilet paper for more information).
- Flush regularly adding water to the toilet bowl before flushing.
- Sanitize your tank after dumping.
For an in-depth article on maintaining your RV holding tanks and drain read How to Keep Your RV Drains Clean, Fresh, and Functioning Properly.
Additional articles on maintaining and emptying for your holding tanks include:
- Sewer Tank Woes
- Why and How to Use Dawn Dish Soap in RV Black Tanks?
- The Best RV Toilet Paper
- 17 Ways to Use Dawn Dish Soap…beyond Cleaning the Dishes
- The 10 Essentials Every RV Owner Should Buy Before Their First Road Trip
- Maintain Your RV: What You Absolutely Need To Know To Avoid Disasters on the Road
Worth Pondering…
Learn from yesterday, live for today, look to tomorrow, rest this afternoon.
—Charlie Brown, from Peanuts
