RV Black Tank Flush System: Everything You Need to Know About

It’s not enough to dump your black tanks when they get full. To properly maintain your RV’s sanitation system, and extend the life of the waste water holding tank it needs to be flushed after you empty it.

Even if you dump them regularly, waste can build up inside the tank and hoses, causing odors and clogs. A good way to prevent this is to flush your black tank with clean water every few months.

I’ve even found that it needs to be done about once a month if you’re living in it full-time. It also needs to be done after every camping trip before you put it in storage.

If you don’t already know what a black tank flush is, what it does, or how to flush your black tanks, keep reading.

By the time you’re done, you’ll have a better idea of how to clean out your black water tanks by using black tank flushing systems.

What is an RV Black Tank Flush?

An RV black tank flush is simply flushing your black water tank with clean water. This will help to remove any waste that has built up inside the tank and hoses.

It’s a good idea to do this every few months, or even once a month if you’re living in your RV full-time.

The black tank flush is an important component of most RVs because it prevents your black tanks from getting so clogged that you can’t use them.

How the Black Tank Flush Works

When you hook a hose up to your black tank flush valve and turn it on, a mechanism inside the tank opens the valve to your black tank and allows water to flow in.

As the water flows in, the mechanism spins and sprays at the same time, covering the interior walls of your black tank and loosening anything that’s stuck.

The water will fill up the tank and then start flowing out through the hoses. As it does, it will push any waste that’s inside the tank out with it.

Where the RV Black Tank Flush is Located

Your black tank flush could be in a few different places. Some RVs have a black tank flush located inside the control panel with the city water connection and the fresh water tank connection.

Other RVs will have the black tank flush located nearer to the black tank. If you have a bathroom in the middle or the back of your RV, you may find the black tank flush somewhere else.

In some cases, you may find the black tank flush inside your RV, underneath a bathroom cabinet. These are a bit harder to get to and aren’t the most convenient.

How Often Should You Flush Your RV Black Tank?

How often you flush your black tank will depend on how often you use it and how full it gets before you dump it.

If you’re living in your RV full-time, you may need to flush your black tank once a month. If you only use your RV for occasional camping trips, you may be able to get away with flushing it every few months.

It’s also a good idea to flush your black tank before you put it in storage for the winter.

This will help to prevent any waste from building up inside the tank and causing odors.

How to Flush Your RV Black Tank

How to Flush Your RV Black Tank

There are a few different ways that you can flush your black tank. The simplest method is to attach a hose to your city water connection and run it into your black tank until it’s full.

You can do this by simply holding the toilet flush down until your black tank indicator tells you it’s full. Then, turn off the city water and let the tank empty.

While this is probably the easiest, it’s not the most efficient. This method can be used occasionally to help prevent odors, but it won’t do a very thorough job of cleaning out your tank.

A better method is to use a black tank flush that’s designed specifically for this purpose.

These devices attach to your black tank flush valve and have a long hose that you can run to a water source.

Here’s a step-by-step guide on how to flush your black water tank using the flush valve:

  1. Park your RV near a water source, such as a hose or faucet.
  2. Attach a hose to your black tank flush valve.
  3. Run the hose from the flush valve to the water source.
  4. Turn on the water and let it run into the black tank until it’s full.
  5. Turn off the water and let the tank empty.
  6. Repeat steps 4-6 until the water runs clear.
  7. Disconnect the hose and close the black tank flush valve.
  8. Flush your toilet a few times to refill the bowl with clean water.

This method will take longer than simply filling up your tank with clean water, but it will do a much better job of cleaning it out.

You may need to repeat the process a few times to get your tank completely clean.

If you notice any odors after flushing your black tank, you can add a black tank odor control product to help eliminate them. These products are available at most RV dealerships and online.

Most black tank valves are equipped with a backflow prevention device that ensures black water doesn’t make its way into your water hose.

However, it’s still important that you use a dedicated hose for your blank tank flush to eliminate the risk of contaminating your fresh water hose.

How Long Should You Flush Your Black Tank?

How long it takes to flush your black tank will depend on the size of your tank and how full it is.

A good rule of thumb is to let the water run for 2-3 minutes each time you close the gate, opening the gate and letting the water run out of the tank between each flush.

If your tank is particularly full or has a lot of waste build-up, you may need to let the water run for longer. Once the water runs clear, you can turn off the water and let the tank empty.

It could take anywhere from 10-30 minutes to flush your black tank completely.

It’s important to note that you should never add water to your black tank while it’s emptying. This can cause sewage to back up into your RV, which is a serious health hazard.

If you notice that your black water tank isn’t draining as quickly as it should, there may be an obstruction in the tank or the hose.

You can use a black tank wand to help clear any obstructions and improve the flow of water.

Cleaning the Tank Without the Flush System

Cleaning the Tank Without the Flush System

Some RVs don’t come with a black tank flush valve, but that doesn’t mean you can’t still flush your tanks when they’re full or causing a foul odor.

If your RV doesn’t have a flush valve, you can use a garden hose to fill up your black tank and then let it empty.

This method is similar to the one described above, but you’ll need to be careful not to overfill your tank.

You can also use a product called a black tank drainer to help clean out your tank without the need for a flush valve.

These devices attach to your toilet and allow you to drain your tank without making a mess.

Be sure to read the instructions carefully before using a black tank drainer, as they can be tricky to use.

There are also plenty of products on the market that will help break down the waste in your tank, making it easier to clean. These products include:

  • Green Gobbler – This is a powdered product that you add to your tank and then fill with water. It’s safe for septic tanks and helps break down waste quickly.
  • RV Digest-It – This is a liquid enzyme that you add to your tank when it’s full. It helps break down waste and make it easier to flush out of your tank.
  • RV toilet chemicals – These are designed to help break down waste and keep your tank clean. They’re available in both powder, liquid, and pod form, so you can choose the option that best suits your needs.

If you add a toilet tank cleaner to your black tank once a week, it will continue to work at breaking down this waste over time, so when it’s time to clean out your tanks, it will go more quickly and be more effective.

Can I Install an RV Holding Tank Flush Myself?

If your RV doesn’t have one built-in black tank flush system, installing an RV holding tank flush system is a relatively simple process that most people can do themselves.

The first thing you’ll need to do is locate the black water tank on your RV. This is usually located under the RV, near the back.

Once you’ve located the tank, you’ll need to remove the cap to expose the opening.

Then, you’ll need to insert the black tank flush hose into the opening. Be sure to use rubber gloves when doing this, as the sewage can be harmful to your health.

Once the hose is inserted, you’ll need to turn on the water and let it run for 2-3 minutes.

Then, you’ll need to close the valve and let the tank empty. Repeat this process until the water runs clear.

You can then remove the hose and replace the cap on the tank.

If you’re not comfortable doing this yourself, you can always hire a professional to install the system for you.

How Do You Winterize a Black Tank Flush?

If you’re going to be storing your RV for the winter, it’s important to winterize your black tank flush system. This will ensure that the system doesn’t freeze and break during the cold weather.

To winterize your system:

  1. Disconnect the water supply and drain all of the water from the lines.
  2. Add RV antifreeze to the system and run it through the lines. Be sure to follow the instructions on the bottle of antifreeze, as some products require you to dilute them with water.
  3. Once the antifreeze has been added, you can then store your RV for the winter.
  4. When you’re ready to use your RV again, be sure to flush the antifreeze out of the lines before using the system.

Final Thoughts

Black tank flushing is an important part of RV maintenance. By following the steps above, you can ensure that your black tank stays clean and odor-free.

If you have any questions about black tank flushing, or if you need help winterizing your system, be sure to contact a professional RV technician.

They’ll be able to help you keep your RV in top shape all year long.

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