12V Marine Waste Water Pump – Diaphragm 20 L/min (Toilet Discharge)

This 12-volt waste water diaphragm pump is specifically designed for marine use and serves to evacuate sewage and waste water from onboard toilets and holding tanks. Being a diaphragm-type pump, it operates without impellers, allowing it to move waste water containing solid particles and toilet paper without clogging and without the need for a separate macerator or filter. The pump is self-priming, meaning it can draw fluid from several feet below or away, which is convenient for installations even above the level of the tank.

High Performance: With a flow rate of approximately 20 liters per minute, this pump quickly removes the contents of a toilet or empties waste holding tanks in a short time. This is especially useful on larger yachts or boats with multiple users, where efficient waste management is important. The inlet and outlet diameter is 38 mm (1½ inches), which is the standard size for marine sanitation hoses – it will easily integrate with existing plumbing.

Special Features: The diaphragm technology allows it to run dry for short periods without damage – i.e., if the tank empties and the pump briefly sucks air, it won’t harm the unit. Additionally, the design includes dual outlet valves to ensure continuous flow and to prevent backflow of waste into the pump. The pump also features a 360° rotatable discharge port, which makes installation easier – you can rotate the outlet to align with your hose direction, avoiding kinks.

The housing and diaphragm materials are highly chemical-resistant, able to withstand the harshness of saltwater and the chemicals found in sewage or cleaning agents used in marine toilets. Weighing about 3.2 kg, the pump is solid and stable, with a mounting base that allows secure attachment to the boat’s structure.

Applications: The primary use of this pump is as a marine toilet waste pump – it can directly evacuate waste from manual or electric marine toilets overboard (where legally allowed) or to a central holding tank. It’s also suitable for emptying holding tanks themselves when you need to pump out to the sea or a deck discharge point. Thanks to its reliability and dry-run capability, the pump can double as an automatic shower sump pump in systems where gray water (from showers or sinks) collects in a small sump and needs to be pumped overboard.

Installation & Use: Mount the pump in a dry location protected from direct splashes, but as close to the source (toilet or tank) as practical for efficient priming. Always use 38 mm (1½") hoses with secure clamps to prevent leaks. The electrical hookup should include an appropriate fuse (around 15 A, per manual) and a suitable switch or automatic float switch. The pump can run automatically if connected to a float switch in a sump, or manually via a switch when needed.

When operating, ensure all tank vent fittings are functional (to avoid vacuum lock). The pump requires minimal maintenance aside from an occasional flush with clean water to clear any deposits on the valves. Its diaphragm design ensures long life and reliability, so you can be confident that waste will be discharged quickly and hygienically, without unpleasant malfunctions or spills. This is a crucial component for maintaining comfort and sanitation aboard any modern boat or yacht.