How to drain a marine toilet on a boat?

Comfort on board, Black water tanks, Marine WC

A marine toilet consists of toilets connected to a clean water tank, as well as to a waste water tank. The waste water tank is the one in which the water expelled from the basin is stored. So the emptying a marine toilet concerns the evacuation of this tank which contains potentially dangerous effluents for the passengers. This apparently simple operation is actually quite delicate. Not only is it subject to a strict regulations on marine toilets, but also, it requires a minimum of know-how. Finally, be aware that our advice can apply to all brands whether those are Jabsco, Albin Pump, Lalizas, Nuova Rade, Johnson Pump, Osculati, Matro, Lavac, Dometic or even RM69.

The equipment needed to drain a marine toilet on a boat

La emptying a marine toilet is an operation whose duration cannot be standard. It all depends on the level of difficulty of the task to be performed. In general, it takes an average of thirty to forty-five minutes for an emptying with a cleaning of the tank. The equipment needed to carry out this type of operation is listed below:

Equipment needed for emptying a marine toilet

Drain filler: this accessory is used for emptying with a suction nozzle at the port.

Flexible but resistant hose : it will be useful for emptying a marine toilet in port, at sea or when sending to a pump.
Thru-hull : it serves as a transfer point between the interior of the boat and the exterior. It is to it that drain devices such as pump hoses and drain hoses are connected.
Drain pump : provide a suitable outlet pipe to the through-hull, if the configuration of your boat requires it.

Anti-siphon elbow: it is essential when the through-hull is located below the waterline (which is not recommended at all). Its role is to prevent wastewater from being returned to the interior during emptying.

See a 38 mm marine toilet anti-siphon elbow

Materials required for cleaning the waste water tank

Water lance : this tool is used to rinse and clean the tank.
Toilet brush: it will help you scrub the surfaces when needed.

Rubber gloves: they limit contact with microbes contained in wastewater.
Specialized disinfectant such as YACHTICON Puryclean : the disinfectant eliminates germs and odors after emptying a black water tank for a boat.

How to drain a marine toilet on a boat?

We would like to remind you that the emptying of wastewater tanks obeys well-defined regulations. So, before you embark on such an operation, make sure you are in good standing by reading our article on marine toilet legislation.

How to drain the dirty water tanks of a boat?

A marine toilet can be emptied in two ways: in a dedicated port station or at sea (far from the 3 nautical mile zone).

Emptying in a port pumping station

Emptying a black water tank for a boat can be done at a port pumping station. This service can be paid or free, depending on the catalog of services provided by the port operator. The service provider connects your boat to a vacuum cleaner which sucks up the wastewater contained in the tank. It is also he who takes care of the treatment and disposal of the collected effluents.

Emptying at sea

Emptying a black water tank for boat is less expensive when carried out at sea, provided that the restrictions and standards defined by law are respected. This operation greatly depends on the positions of the toilet and the black water tank in relation to the waterline.

Toilets and black water tank located below the waterline: the emptying of such a tank imperatively requires the use of a drain pump to evacuate the water through the through-hull.
Toilets located above the waterline and tank below: as in the previous case, you must have a drain pump.
Toilets located below the waterline and tank above: if the tank is horizontal, you must have a drain pump to drain the black water through the through-hull. But if your tank is vertical and positioned at least 50 cm above the waterline, it can be drained by gravity.

Toilet and tank located above the waterline: if your tank is horizontal, you will need to use a pump to remove the sewage from it. However, if it is vertical and placed at least 50 cm above the waterline, it can be emptied by gravity.

How to clean and maintain the waste water tank?

Now that you've drained your sewage tank, clean it out. To do this, use the water lance (with gloves of course) to spray the walls with a jet of pressurized water. Do it from the deck filler, valve open, for more efficiency. Make three to four passes, and finish off in style, pouring in a sanitary cleaner such as YACHTICON Puryclean to fight against odors and germs.

Our advice for emptying your marine toilets

Observe wastewater regulations: as we said above, the emptying of marine toilets is governed by strict laws. Find out about the relevant standards and restrictions to avoid fines (some go beyond € 4).

Take care to protect the environment: make sure that the methods and products used during your oil changes respect the environment.
Install a meter to know when to drain: use a gauge specially adapted for black water tanks such as the osculati kit. It includes a meter and a probe with universal attachment for tank with a height of 15 to 55 cm (the sensors of the probe must be cut according to the height of the tank used.) NB: you may need a universal joint for the probe if it is not supplied with your tank.