A seawater desalination machine takes raw salt water and turns it into safe, clean drinking water using reverse osmosis. If you are shopping for one, the core question is simple: how much water do you need per day, and how do you want to power it? Everything else, size, price, portability, flows from those two answers. This guide walks you through the key decisions so you can match the right machine to your actual situation.
How a Seawater Desalination Machine Actually Works
Seawater enters the unit through a pre-filter that catches sediment and particles. A high-pressure pump then forces the filtered water through a semi-permeable reverse osmosis membrane. The membrane rejects the vast majority of dissolved salts and lets fresh water pass through. The salty concentrate is discharged overboard. On a quality marine unit the membrane rejects around 99.4% of salt, bringing output down to under 800 ppm TDS, typically 250 to 300 ppm on a LEDI system. That is well within Australian drinking-water standards. A built-in UV stage provides an additional treatment step before water reaches your tank.
The process requires no chemicals, no heat, and no complicated controls. The main inputs are seawater and electrical power. On a 12V system that power can come straight from your house battery or solar panels, with no generator needed.
The Three Specs That Actually Matter When You Choose
- Output in litres per hour (LPH). Match this to your daily water budget. A cruising couple on a 30 ft yacht typically uses 10 to 20 litres per person per day. A larger crew, liveaboard, or charter operation will need more.
- Power source and draw. A 12V DC machine with a 16 to 18 amp draw runs comfortably from a standard house bank with 200 to 400 W of solar. A 240V or mains-dependent unit needs a generator or shore power.
- Portability vs permanent install. A portable unit needs no plumbing, no through-hull, no installer. A permanently plumbed system disappears below deck but requires professional fitting and is tied to one boat.
Salt rejection, pre-filtration quality, and serviceability round out the list. A machine that nobody can service in the field is a liability on a long passage.
Portable Desalination vs Fixed Install: an Honest Comparison
Fixed watermakers installed below deck on a cruising yacht typically cost $10,000 to $25,000 installed in Australia, once you factor in labour, through-hulls, a dedicated electrical circuit, and proprietary parts. They are tidy and automated, but if the pump fails offshore you often need a specialist and specific parts on order.
A portable seawater desalination machine like the LEDI Scout starts from $4,899 AUD. Drop the stainless intake over the side, connect the hoses supplied, plug into your 12V outlet, and you are making water in minutes. Every wear part is a standard, non-proprietary component available from LEDI and most marine suppliers worldwide. Because LEDI makes the Scout on the Gold Coast, there is no importer markup or overseas freight on an 18 kg case. That is the main reason the price sits well below equivalent European or American fixed systems.
Portability also means one machine can move between boats, serve as a backup to a fixed unit, or go on a 4WD trip. A fixed system cannot.
Matching the Machine to Your Crew and Boat
The right choice depends on crew size and how you use the water.
- Scout 10 LPH or 20 LPH ($4,899 from): Suits trailer sailers, coastal cruising yachts 20 to 50 ft, catamarans with smaller crews, and campers or 4WD tourers. Eighteen kilograms, single-person carry. Run it for a few hours each day and you cover most couples or small crews easily. The Scout uses a Pumptec 107SS high-pressure pump from the USA, rated to around 800 PSI, and 316 stainless components throughout.
- Nomad 40/60/80 LPH ($9,899 single-membrane): Built for bigger crews, liveaboards, long passages, charter use, or anywhere you want a shower underway without rationing. The Nomad runs on 12V or 24V DC (240V via mains adapter), includes an integrated control panel with TDS monitor and flow meter as standard, and weighs around 38 to 42 kg. It uses a Cat Pumps 2SFSEEL 316 stainless high-pressure pump that is fully serviceable in the field.
- Modular: If you want the machine hidden below deck in a refit or new build, the Modular range is designed for semi-permanent or permanent installation with a remote control panel and auto freshwater flush. Contact the LEDI team for a configuration quote.
One rule worth knowing: if you need around 30 LPH, the answer is a Nomad 40 run fewer hours, not two Scout units side by side. Two machines means double the maintenance, double the connections, and extra complexity for no real benefit.
Power: Running a Desalination Machine on Solar
The Scout draws 16 to 18 amps at 12V. A typical cruising yacht with 200 to 400 W of solar and a decent house bank can run it comfortably during daylight hours or from stored charge, with no generator needed. If your solar setup already handles a fridge, lighting, and navigation instruments, adding a watermaker is usually a matter of scheduling when you run it, not upgrading your whole electrical system.
This is a meaningful practical difference from generator-dependent fixed systems. No diesel, no noise, no fuel budget to manage at every anchorage.
See the full walkthrough in Running a Watermaker on Solar Power: A Practical Guide.
Feed Water Quality and Pre-Filtration
A seawater desalination machine is rated for seawater up to 35,000 ppm, but most units also handle brackish water and river water at lower salinity. The LEDI Scout and Nomad are both rated for feed water up to 40 degrees C.
Pre-filtration protects the RO membrane. The Scout ships with a 5 micron pre-filter cartridge. In clean offshore water you can expect to replace it every 30 to 40 running hours. In silty harbours or river water that drops to 10 to 20 hours. A new Scout pre-filter cartridge costs $25 AUD and takes minutes to swap. The Scout is also compatible with a larger 2.5x10 inch pre-filter housing if you want to extend time between changes in dirtier water. The RO membrane itself is not a routine consumable: with proper care (freshwater flush after use, pickling for storage) it lasts several years.
For a deeper look at membrane care, see Watermaker Membrane Lifespan: What Shortens It and How to Make Yours Last for Years.
Servicing, Warranty, and Spare Parts
LEDI offers a 1-year warranty on every unit, extended to 2 years when you register the machine. The team provides lifetime in-house servicing on the Gold Coast. All wear parts, filters, membranes, and pump service kits are available from LEDI's spares collection and post Australia-wide and internationally, usually within one business day. Because every component is a non-proprietary, off-the-shelf part, a competent owner can handle most maintenance anywhere in the world.
Both the Scout and Nomad have an internal hour meter. Track those hours and you will know exactly when pre-filter changes and pump service intervals are due.
Frequently Asked Questions
What is the output of a portable seawater desalination machine?
The LEDI Scout produces 10 or 20 litres per hour. The LEDI Nomad produces 40, 60, or 80 litres per hour depending on configuration. Output can vary slightly with feed water temperature and salinity.
Can a seawater desalination machine run on 12V solar power alone?
Yes. The Scout draws 16 to 18 amps at 12V. A house battery with 200 to 400 W of solar handles it comfortably during daylight hours with no generator. The Nomad also runs on 12V or 24V DC.
How often do filters and membranes need replacing?
The pre-filter cartridge is the routine consumable, typically every 10 to 40 hours depending on water clarity. A replacement cartridge costs $25 AUD. The RO membrane is not a regular consumable and lasts several years with proper flushing and storage care.
Does LEDI ship seawater desalination machines outside Australia?
Yes. LEDI ships worldwide direct from the Gold Coast. Freight is calculated case by case, so contact the team for a quote. Import duty or GST charged by the destination country is the customer's responsibility. LEDI has no overseas distributors or agents, so everything comes direct.
Ready to talk specifics? Contact the LEDI team at info@ledi.com.au or call +61 494 562 668. You will speak with a real person who can match the right machine to your boat, crew, and power setup.
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