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Where Is The Black Water Tank On An RV?

If you are using any water aboard an RV, you'll have to empty the black water tank at some point. While a bit of a chore, it can be easily completed with a little bit of practice and know-how. The first step will be locating the tank itself. We researched RVs in detail so you'll know exactly how to locate this part.

The black water tank is located under the RV carriage. It will be next to the grey water tank.

Now that we know where to look for the black water tank, we'll take a look at the steps you need to take to empty it safely. You might also be wondering how you will know when the black water tank is full or how often it will need to be emptied. For the answers to these questions and more, read ahead in this post to see what our research has shown.

Motor home and sunset during springtime, Where Is The Black Water Tank On An RV?

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Locating And Emptying The Black Water Tank

Getting access to the black water tank on your RV is really easy. This wastewater tank will be located under the RV close to where your bathroom is on board.

You won't need to crawl underneath the RV to get access to it, however. The port to empty both this and the grey water tank will be underneath the RV but near the exterior sidewall.

Now that you see the ports used to empty these holding tanks, you'll be able to take the few steps needed to empty them. Follow these steps in order, and you'll be finished in no time.

1. Gather The Equipment And Supplies You Need

Your RV will have the drain hose for the water tanks stowed away. Grab it from its storage spot. You'll also need disposable rubber gloves, anti-bacterial wipes, and a few rags.

Put the gloves on and you'll be ready to get started.

Man wear gloves

2. Drain The Black Water Tank First

Hook the drain hose up to the drain port, carefully connecting the other end to the wastewater port at an approved disposal location. Double-check that both ends of the hose are secured in place. This will avoid making a huge mess!

Man emptying RV sewer at dump station

Open the valve from the black water tank. Be sure to open it fully. This will allow the contents of the water tank to drain completely. Be patient, as this process could take several minutes.

3. Follow The Same Process To Drain The Grey Water Tank

When the black water tank has been emptied, it's time to move on to the grey water tank. Close the black water tank valve, then open the grey water tank one. This will flush all of the water from this tank through the hose and out of your RV.

Man emptying caravan tank toilet cassette in dump station

It's important to empty the black water tank first. This tank is the dirtiest, as it holds human waste. Flushing the water from the grey water tank afterward helps to cleanse much of this waste from the drain hose. This makes your final cleanup a lot easier.

After it is empty, close the valve for the grey water tank.

4. Flush The Hose

This step should be taken if you have a good source of fresh water nearby. Flush the hose from the freshwater valve, helping to remove any leftover human waste from the hose. While this step isn't absolutely necessary, it will help keep your drain hose much cleaner.

Don't forget to replenish your freshwater tank after you're finished!

5. Double-Check Your Work

Remove the hose from the drain port. Check and make sure that you have closed all valves completely. Remove the other end of the drain hose from the disposal port. Make sure that you haven't left any used wipes or rags anywhere on the ground.

6. Clean Up

Stow the drain hose back to its proper location. Use anti-bacterial wipes to clean the ends first. Then, use the wipes to clean the areas around the drain valves.

Man rmptying RV sewer at dump station after camping

You'll want to add a bit of water to your black water tank before you use the RV's toilet again. Add your preferred chemicals at this time to aid in the breakdown of any future solid waste that will enter the tank.

How Can You Tell When The Black Water Tank Is Full?

There are several ways that you can tell when your black water tank is getting full. The most technical method is by being alerted by the sensors in the tank. When the tank is almost full, these sensors activate, warning you that you'll need to find a legal spot to dump the black tank soon.

But many avid RVers will tell you that these sensors aren't always accurate. Even with proper chemicals and the right kind of toilet paper, these sensors can get obstructed. When this happens, you need to rely on your senses. 

You will notice the odor coming from the toilet getting stronger. The fuller the black water tank, the stronger the smell. And if this doesn't signal that the tank is full to you, watch for black water bubbling back up into the toilet after you flush it.

Woman emptying RV Sewer

How Often Should I Empty The Black Water Tank?

There is no set time that your black water tank will need to be emptied. How often you'll need to do this chore will depend on how much the toilet is used.

Many seasoned RV travelers will be able to put off emptying this tank for quite a long time by using bathrooms at campgrounds and only using the one aboard the RV for emergencies.

No matter how long your trips are or what your rate of using the bathroom in the RV might be, you should always empty the black water tank at the end of every trip. This keeps the black water tank contents from solidifying in the tank as the water slowly evaporates out of it.

We should also point out that experts recommend emptying the black water tank when it is at least 2/3 full. This means that there will be more liquid than solids in it, making it much easier to empty. It also helps in avoiding pesky clogs.

Is It Legal To Dump From A Black Water Tank At Home?

You might be relieved to know that you do not have to do a frantic search for a campground near your home for the draining of your tanks. It is legal to do so from your own home. But you can't just empty your black and grey water tanks in any sewer.

Tank toilet cassette in dump point during road trip

You can dump your tank's contents into your toilet using a bucket, but this is a very time-consuming and potentially messy process. Any approved wastewater access port into a municipal sewer system will work. But check with your local government first.

Avoid dumping your tanks into stormwater systems. This is not only harmful to the environment but it is unsafe and illegal. 

Final Thoughts

Locating the black water tank on an RV is quick and easy. Discovering its location is the first step in draining the tank which will need to be done with some regularity on your RV travels.

Follow the steps for draining the black and grey water tanks fully and in order, and you will be back on the highway in no time. Drive safe!

We hope this post on RVs answered all of your questions. For additional helpful information, we recommend reading the following posts:

RV Water Heater Isn’t Working On Electric Or Gas – What To Do?

How To Keep RV Cabinets And Drawers Closed When Traveling

How Much Does An RV Gray Water Tank Cost To Replace?