Emptying Your Boat’s Holding Tank // Black Water Tank
There are two methods of emptying your holding tank; one is to travel at least three miles offshore and empty there, and the other is to come to a fuel dock that has a waste pump out, and empty the MSD – Marine Sanitation Device – there.

Pump Out Station
If you are pumping out at a pump out station, these are modern times! There is no more having to put huge amounts of downward pressure on the exit tube, or much risk of the tube popping out.
Most facilities now have serval standardized caps that screw into the boat and are the correct size! This is wonderful! This is brilliant!

First
First, locate your waste cap. Make sure not to mix it up with fuel or water. These three fluids should not mingle.
When you’re sure you have the correct, remove it. There will not be a chain holding it to the deck plate, probably, because it is necessary to completely remove it in order for the exit line tube to be inserted.

Next
The attendant is going to take care of just about everything. They will insert the nozzle, start up the pump, and run the machinery.
There is not a gauge on exiting fluids, like on a fuel fill up, so you won’t really know how many gallons you are just to sending. There is a sight window, however, so you can see what’s leaving the boat.

Assistance
It’s quite acceptable to look at your holding tank gauge, if you have one, and give the attendant and idea like, “halfway there,” Or “3/4 of the way to empty.”
There probably are no funny jokes that you can tell at this time, as the attendant will have heard everyone of them at least 50 times each.

Flushing
When it seems that the tank is empty, you might opt to pump more water through the toilet, and empty that as well, sort of “flushing it out.”
The attendant will remove the nozzle, they might possibly suck up a bit of sea water to flush out their own line, and their job is done.
A gratuity for performing this valuable service for you would be appreciated by the dock hands, especially if they helped you get to the dock.

Pumping Out Offshore
1. Gravity Fed System
We’ve only had one gravity tank in our fleet, and it was a pretty simple process of opening up valve, listening for “things “to fall out of the boat, and then closing the valve.

2. Electric Macerator System
For a more traditional macerator set up, you will need to open the macerator line’s thru hull fitting in the bilge or in a lazarette so the fluids can exit the boat.
On your electrical panel, there could possibly be as many as two buttons. One that is able to switch on and off, which supplies power to the pump.
Then a second switch, much like the bilge pump switch, that must be held in position, and once released, springs back to not running.
Think of this like a drill with a cord. It is plugged in, but not running. It requires your finger on the trigger to run, and when you let go, it quits running.

Power to the Pump
You’re going to turn on power to the pump, and then hold down the macerator button. The end of the button might turn red, indicating that it is performing its function, and you should hear a pump running noise.

How Will I Know…
In sailing class, everyone wants to know how will we know that the tank is empty. There are two methods.
One is for someone to position them self topsides, near the release valve, and watch. They will notice a lot of brown material in the water, then slightly more clear muddy material, then clean water flushing if you are running some water through the toilet to flush things out again.
As you rock and sail over waves, more material will flow out of the boat.
If that’s not possible, then listen. The macerator pump will sound like making a frozen drink, only not so violent.
First you will have more “rocky” type of noise, sort of like making a frozen drink and first grinding up the ice. Then, when the tank is closer to empty, the motor will free wheel and spin, like a frozen drink nearly completely blended.

3. Hand Pump Out System
If you are using the third system, a hand pump, you still must open the holding tank thru hall valve.
Go to where the pump is, and pump and pump pump until things run clear. It might take a bit of priming at the beginning to get the process started.

Close the Thru-Hull
Whether you are using an electric exit pump, or a manual exit pump, when finished; absolutely definitely make sure that you close the thru hull valve.
The action of you sailing along can allow backflow to enter the toilet, boil over the lip, onto the head sole, into the shower – you get the idea.
Close the macerator thru-hull fitting when finished, and de-power the pump on the electrical panel.
What to read next: 5 Things to Check Before Backing Your Boat Out of a Slip

Into the Water
Don’t forget that everything that touches your body can end up in the water.
Shampoo, conditioner, deodorant, toothpaste – everything gets into the water. Be sure your choices are biodegradable.
For extra-eco-conscious choices; select products that have biodegradable containers, and made from recycled materials – trips good!
If you are looking for ecoconscious choices, Stream2Sea offers water-, reef-, and human-safe products tested to be safe for the environment.

I Don’t Go Anywhere Without:
- North American Rescue CAT tourniquets.
- PierShare to rent your dock out or rent a dock.
- BoatUS for your boat towing insurance! Code: “HEWAF88”
- Thank you Bill for being the Best Sailing Partner EVER!