How to Dump the Tanks in a Trailer (Easy Beginner’s Guide)


Dumping tanks is probably an RV owner’s least favorite task when it comes to adventuring and camping. Hopefully, this guide will get rid of some of that fear and disgust and will bestow on you all the basic information you need to know about how to dump the tanks in a trailer. 

How do you dump the tanks in a trailer? To dump the tanks, first put on silicone cleaning gloves. After that is done, attach the hose to the downspout, and put the other end in the hole of the dump station. Release the black tank valve first and then the gray tank valve.

That’s really all it is. 

It’s a gross job, but the process is a pretty simple one. The steps are pretty simple and are not hard to do. A tank needs to be emptied pretty diligently and frequently so there isn’t any overflow. When dumping, just be sure to be as safe and sanitary as you can. 

Step-By-Step Guide

This first step by step guide is not the only way you can dump your RV tanks, but it is the most common and advisable way to dump. The equipment involved sometimes comes with the RV, but it mostly bought separately.

To be able to dump your tank you will need a sewage hose, water hose, an elbow adapter and dump adapter. All three are used to either dump waste or clean up after waste.  Below is a detailed step by step guide to help you empty out your tanks correctly.

Step 1

When entering the RV dump station, pull the black tank valve as close to the dump station as possible. This won’t prevent messes but will help to minimize the range of the mess. Always do the black tank first before the gray tank. (Even if they are on opposite sides and you have to turn the RV around.)

Step 2 

Sanitary protection is extremely important when emptying out an RV tank. Put on silicone cleaning gloves or latex disposable gloves to protect yourself from germs and disease causing feces. 

Don’t open the black and gray tanks just yet!

Step 3

Attach the hose to the dump station drain first. Use an elbow and  hose ring to help you in avoiding splashes and messes. If you don’t have either, push the hose in a little further and place something heavy on top of it. This will help prevent the pressure from causing the hose to pop out of the dumping hole. 

Step 4 

After you have completely hooked up the hose to the drain tank, you can proceed attaching it to the black water tank. When doing this, you need to be catching any drips and rechecking to make sure that the hose is secured tightly. You wouldn’t want it to come undone while you are emptying the tank. 

Step 5

Open the black tank valve and let it completely empty. You should be able to hear almost nothing by the time it’s finished. Once it’s done then you can proceed to the next step. 

Do not proceed to the next step until you are sure that all the black water has been emptied into the dump station. 

Step 6

There are two ways you can do step six. The first: Use the vehicles rinse system it comes with. Let the rinse system run for about 2-3 minutes to flush out leftover fecal matter. 

The second: If your vehicle does not have a built-in rinse system then you can fill up your toilet with water and flush. Do that 2-3 times to get rid of those solids. 

Be careful when using the rinsing system as it is easy to forget that you’ve turned it on. If you forget about it, it will overflow into the trailer. 

Step 7

Close the valves. Unhook the hose from the RV and lift it so that any remaining waste is emptied into the dump station. 

Step 8

Hook the two ends of the hose together and put it away. Rinse around the dump area for any waste that may have escaped and make sure it’s clean. 

Below is a video that shows you how to hook up your hose to the black/gray water spout and the dump station. 

Where do I Store the Hose Once I’m Done?

Every RV is different, but most of them have 2 options for storage. The first option is an empty space in the bumper where your hose can be stored. Other vehicles have a PVC tube you can slip the hose into for storage.

Both options will keep the hose away from anything it could touch and contaminate. Even though you’ve maybe rinsed it out pretty good, it’s still not a safe object to have around anybody; especially near children. 

Sanitation Precautions

In every thing that you do make ysure that you are careful with the black tank. Always wear gloves and properly dispose of those gloves when you are finished emptying the tank. 

Wash any surface you may have touched while wearing the gloves and wash your hands as well! Even though you were wearing gloves waste and germs could still get through if you had a leak. You don’t always know if you do. 

Don’t be afraid to even wash all the way up to your elbows either. Sanitation is very important especially since dumping a tank requires you to have the possiblity of coming in contact with human waste. 

Do not allow little children near the dumping area. LIttle children are more susceptible to diseases causing germs than adults. Not only do the tanks contain fecal matter, but chemicals as well. It’s best to keep little children away from the dumping process. 

How Often Should I Dump My Tank?

When your black water tank is about 2/3 of the way full you should dump. You should try and minimize how often you dump because more time means the waste will be able to break down more. 

Try to dump about every 3-4 days or once a week. It probably sounds gross to leave all that waste in your RV for too long, but it’s actually better because it makes it easier to dump. 

Waste that has been broken down has a better chance of moving through the pipes/hoses of the dumping station and not getting clogged on the way down. If they haven’t had enough time to break down you might have a mess on your hands. 

The grey water tank can be dumped more often because there isn’t really anything that need to be chemically broken down. A grey water tank should be emptied about the same- 2-3 times a week.

Where Do I Dump It?

The best place to dump your tank is at a dumping station designed specifically for that purpose. It is simple and is a lot less difficult and messy than doing it somewhere else. 

Some people think that they can dump where there’s sewer and get away with it. One man even stated to me that he saw a man dumping into a manhole. Dumping in a manhole is illegal. 

If you dump in a manhole, the waste doesn’t have a chance to go through a filter. It will go straight into the ocean and other clean water areas created unsanitary conditions.

When you dump at a designated dumping station the water has a chance to go through the right processes to be cleaned and filtered. The waste is disposed in such a way that is safe for the rest of the world. 

On the other hand, it isn’t illegal to dump your tank into your home sewer. However, it needs to be done correctly. If done incorrectly, your septic tank can overflow and cause messes and damage. 

How Do You Dump a Tank into Your Home Sewer?

Before I get into the details of how to do this, let me advise you to use a dumping station. It is a lot less risky for your sewage system and dumping stations are all over the country. There is no need to wait till you get home to dump.

A home sewage system can only handle a certain amount of waste and a certain amount of pressure by which that waste is emptied into the tanks. 

It all depends on how much waste that has accumulated. If you’ve got a lot of waste, definitely go to a dumping station. If you’ve got just little, it is possible to dump in your septic tank if that’s what you’d like to do. 

You’ll need a few things if you are going to dump your tank into your own sewer. These items will need to be bought anyway for dumping purposes when taking your waste to a dumping station. They are as follows:

  • Portable RV Waste (Macerator) Pump:
  • Rinse Hose
  • Elbow Adapter (There is an option with clear plastic that would allow you to see the waste and it passage through the hose. It’s a good option for being able to gauge your waste flow.)
  • Clean dump adapter
  • Waste Hose (Link includes elbow and clean dump adapter)

Attach the Macerator pump to the gray/black water tank and then connect the water hose or the sewer hose. Apparently, you don’t need to use the sewer hose here because the Macerator pump is cutting/blending the solid waste into a more liquid form. 

Note: When plugging in the Macerator pump to dump your tank into your own sewer, you can’t plug it into your house outlet. The power level isn’t compatible. You are better off connecting to your RV/Car/truck battery with jumper cables.

Some people try and connect the Macerator pump to the cigarette port as well, but this will put too much for your car. Your best bet is to attach the jumper cables. (It is possible to blow a fuse but isn’t likely. Anyway, those are easy to replace.)

The whole process is very similar to what you do at a dumping station. The only difference between the dumping station and doing it at your home is that one of them uses the Macerator Pump. 

It is also possible that you may need to get longer cords when dumping at home. A lot of the time when people choose to dump at home they have to be further away from the dumping point. This is called long distance dumping. 

It is ideal to be as close as possible to minimize the mess- which is why dumping at home isn’t advisable- but that doesn’t mean it isn’t possible to do it from farther away. 

What is the Difference Between a Gray Water and Black Water Tank?

Gray water refers to the water from the sink and everything else that isn’t the toilet. It’s separate from the excrement. It’s generally cleaner and safer than the toilet water. 

Black water tank is where everything from the toilet goes. The reason you open the black water valve first when you are emptying the tanks is because the gray water will help rinse out much of the residue caused by the black water. 

The black water is toxic and can cause people to get sick. It is important to maintain good sanitation when emptying the black water tank. 

How Do I Keep the Tank As Clean As Possible?

With all that nasty waste getting put into your tanks, you may wonder how you can keep them clean. (By keeping your tanks cleanliness maintained, it is easier for you to dump them later. Certain cleaning products break down what’s inside the tank.)

You can clean both tanks roughly the same way. There are many different products out there for cleaning your black/gray water tanks, but I’m only going to mention two. 

Whichever method suits you, both are good methods. I prefer to use the most effective and economical. 

Black/Gray Water Tank Cleaning

The black water tank is probably the one that needs the most maintenance and cleaning. Here is a DIY recipe from the Terry Town RV Superstore website for cleaning out your black water tank.

Here are the ingredients:

  • 1 C. Borax
  • ½ C. Pine-Sol
  • 3 Tbsp. ammonia
  • One-gallon jug (an old milk jug will work)
  • Hot water

Follow these steps:

  1. Place the Borax, Pine-Sol, and ammonia in the jug.
  2. Add about half a gallon of hot water.
  3. Shake the jug to mix.
  4. Fill the rest of the way with water.
  5. Don’t forget to mark the jug to let others know it’s poisonous.

This recipe wields about 8 treatments for a 55 gallon tank.

If you don’t want to use this recipe, you can go and buy some black water tank treatment on Amazon for about twelve bucks. Some people like to use DIY, but it’s also a good option to buy professionally made treatment. 

This cleaning process is not to be done until after the tank is empty. The cleaning solution is not meant to be placed inside a full tank. 

Rinse out the tank as much as possible. It should be running almost clear; that’s how you know if it’s been adequately rinsed. Pour the DIY cleaning solution into the tank and let it sit there for a while as you travel like you would the store bought stuff. When you arrive at a dumping station, dump it like you usually would regular waste. 

RV Break Down Chemicals

Because of the solid nature of some of your RV waste, it is necessary to have an chemical agent with which to break it all down. There are several chemicals that can be used for this. These chemicals can also be used to help contain the stench that may occur from the black water sitting stagnant for long periods of time.

To help break down this black water, you can use tablets, liquids, packets, etc. The packaging will have the specific instructions to help you know how much to put in- though you usually don’t need to put that much in. 

To utilize these chemicals, the usual method is to flush them directly down the toilet as that will lead to the black water tank. Remember that there has to be at least a good base of water already in the tank for the chemical to be useful.

Note: Do not use any chemicals which contain formaldehyde. It will just make the smell worse. 

Otherwise, you’re just dumping chemical into a dry tank and it will be extremely concentrated. It can also create clumps in your tank that cause it to clog. The last thing you need is a clogged tank. That’s a whole different post! 

Just be sure to follow the instructions on the bottles and/or boxes your toilet chemical comes in. Amazon has a great RV chemical that my family and I like to use for our RV. 

Whatever you choose to use be sure that it does not contain formaldehyde and gets the job done. You don’t want to spend a whole camping trip having to smell your black water tank contents.

Tank Addition and Sizing

Your tank size for your RV is going to change how long it takes you to dump those said tanks, and how often you have to do it. If you have a smaller tank, you’ll need to dump them more often than large tanks. 

Your tank sizes will range from about a 3-gallon minimum capacity to a 150-gallon maximum capacity. For example, a 30 gallon max capacity takes about 3 minutes to dump, whereas 100 may take longer than that. 

The higher your capacity goes up, the more expensive the tank gets as well. You can purchase extra outside tanks for when you are traveling for a long time and need that extra sewage/water space. 

There are tanks which can you can purchase called portable black/gray water tanks. These are tanks that you can roll around on wheels and all you have to do is tip it to dump it. It can get very heavy when it’s full, but it’s smaller (obviously) than the tank you carry in your RV and it is more portable. 

What is the Portable Tank For?

A portable tank can come in really handy when you want to travel long distances and you need to travel long distances and need extra space. 

There are two ways in which you can utilize portable storage that I know of. There is one for black water storage and the other for gray water storage. It’s not likely that you will need it for gray water storage. Most will use it for black water (or both types of water.)

You’re probably wondering how to empty your portable tank. Well, here’s a video that shows you how to do that better than I could tell you.


You always want to keep in mind that whenever you are dumping waste you should be doing it in a designated dumping station or other appropriate areas. Dumping on the street, streams, lakes, or other public areas is not an option. 

It is important to remember that human waste is a bio-hazard and can cause people to get sick. That’s why you should always take extra care when you dump human excrement. 

I hope this article was helpful for you and you are able to now be a professional RV tank dumper. Good Luck!

Related Questions

Can I leave the grey water tank open? Leaving the tank open is not going to hurt anything, but it will smell. If you choose to leave it open you’ll just have to bear the smell. If you leave it closed you’ll have to keep a close eye on the water level.

Is there a special kind of antifreeze for RV toilets?  You can’t use regular antifreeze you would use for a car in RV toilets and sinks. There is a special type of antifreeze for that job which will not cause damage to the lining of your pipes. This antifreeze usually has a label which specifies its use. 

How often should I clean my black water tank? You should be cleaning your tank about once a week or once every two weeks. Just emptying and rinsing is not enough to keep the tanks clean. 

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