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How to Pump Out Boat Holding Tank at Home?

Written by J. Harvey / Fact checked by S. Numbers

how to pump out boat holding tank at home

How to pump out boat holding tank at home? Pumping out your tank is an important skill to learn. However, it might sound like a lot for a beginner that has just started boating.

Yet, you don’t want to empty your tank at a dump station. Do not worry, because you can quickly learn how to do it yourself.

Take note that emptying your tank at home requires a cleanout. It will help dispose of the waste safely, whether you’re on a city sewer or septic system. Nevertheless, this guide will show you how to do it correctly.

VERY IMPORTANT: Do not empty the black or gray water tank directly into your home’s toilet! Otherwise, clogs may be an issue as toilets cannot be used to hold a large volume of waste coming from a boat or RV holding tank.

Three ways to dump the tank include:

  • Bucket method
  • Maceration
  • Dumping without macerating

The Bucket Method


At some points, many boat owners end up using this method to empty the tank. However, it is only ideal for emptying tanks with a small amount of waste. Do not try this method if you’re dealing with a large amount of waste. We’re only recommending this to boaters who are disposing of a few gallons of waste.

What you will need

  • Face covering
  • Gloves
  • A 5-gallon bucket used exclusively for emptying a tank (not for other purposes)

Step 1: Wear a protective face covering and a pair of gloves.

You need to wear a protective face covering and a pair of gloves before beginning with this task.

Step 2: Get your bucket. Use it only for emptying the tank. Please do not use it for any other purposes.

For sanitation, use this bucket only for this purpose. You can get one from home depot, Amazon, or any other stores selling RV/boating accessories and tools.

Step 3: Place the bucket under the gray/black water tank.

Under the tank, place the bucket. Slowly open the valve. Start emptying the tank. Fill the bucket with the waste. When you’re done, close the valve carefully. It is crucial to open the valve slowly to prevent the waste from splashing and making a mess.

Step 4: Dump the waste into the city sewer or septic port.

The cleanout PVC pipe is above the ground. Typically, you can find it between your house and the tank (or the sewer). It has a screw cap that you can unscrew to dump the waste directly into the PVC pipe.

Step 5: Repeat the same process.

If your tank isn’t empty yet, repeat the process. Once done, you must clean and disinfect the bucket before storing it.

Pro Tips

  • You can also use an access port if your septic doesn’t have a cleanout. However, you must be very careful because the access port can let out the harmful gases inside the septic tank. These gases can be dangerous or even fatal when inhaled. And if using the access port, you must choose one that is closest to your home.
  • Make sure to pour on the right side of the baffle. Be careful not to pour waste on the baffle’s wrong side. Which one is this? It’s the farthest baffle from your home. The baffle is what keeps the solid waste from clogging your outlet. It is in the middle of your septic tank.
  • If using the access port, don’t leave its lid off for a long time because it can kill the good bacteria that break down the septic tank’s waste.
  • Again, do not dump the waste into the toilet, or it will get clogged. It can also cause the clogging of your plumbing system, which will result in expensive repairs. So, if you don’t have a septic system, you might want to pump out your boat at the dump station.

The Macerating Method

This method of pumping out your boat is an alternative to the bucket method, which might be gross for some people. But then, the macerating way is a complicated process, so you should be ready for that.

This method involves crushing the waste with a macerator pump that connects to the garden hose. It works by breaking down the waste. The macerated waste is directed or channeled into the cleanout port or septic tank.

You can use the macerating method to break down the waste into smaller particles before dumping it in the septic tank. This method can be useful when dumping your boat’s waste at home, but it can be time-consuming. It can also cost more money to obtain all the macerating pump and other tools.

Things you will need

  • A macerator pump that crushes waste materials
  • A hose adapter
  • A CDFJ adapter
  • Dedicated garden hose for the dumping of waste

Step 1: Get your hose adapter.

Connect the macerator to the waste outlet of your boat using the hose adapter.

Step 2: Get the CDFJ adapter.

Connect the macerator pump to the garden hose using the CDFJ adapter. Then, connect the hose’s other end to the septic tank. You might also shorten the distance that the waste is traveling through your garden hose to avoid straining the pump.

Step 3: Plug in the macerator pump.

Open the boat’s waste outlet valve before turning on the macerator pump.

Step 4: Pour clean water into the boat’s system until it is clean.

Do it until the water coming out is clean and clear. It means that you have emptied the boat’s tank successfully. When done, you can disconnect everything.

Pro tips

  • Some might suggest funneling the waste into the toilet and flushing it, but we do not recommend doing that because it can be messy. You can avoid this hassle by dumping the macerated waste into the cleanout port.
  • Avoid adding chemicals into the septic tank. Use only safe holding tank treatments if dumping into the home’s septic system.
  • Always check for local codes or homeowners’ association rules to ensure dumping waste tanks at home is allowed.
  • The bucket method might be for you if you’re emptying a tank with a small amount of waste.

Alternative Method: Dumping without Maceration

This method is more straightforward than the macerating way. It is also less time-consuming than the above process.

In this method, you will dump the boat’s waste into the access port or cleanout. It only requires connecting the tank to the cleanout port using the sewer hose and flushing the waste later.

Empty the tank into the cleanout port. However, please do not add the waste too quickly, or it will overload the tank and start pushing the undissolved waste into the lateral line.

Do not disturb the scum layer as much as possible if you’re accessing the septic tank through the access lid. Remember, dumping waste directly into the septic tank can damage the septic, so be careful.


How to pump out boat holding tank at home? They are the bucket method, the macerating method, and the dumping without the macerating of waste. Use the one that applies and works best for your situation. Nevertheless, follow the steps and be mindful of the reminders on how to empty the boat’s tank correctly and safely. Besides, if you have interesting with ways to drain gas from boat fuel tank, you can check it out here.

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