
GASOLINE Rainman WATERMAKER
True portability – The gasoline rainman watermaker utilizes an onboard honda GXH 50 engine to mechanically drive the internal pumping components. 1/4 gallon of gasoline will operate the system for over an hour – enabling the production of up to 37 GPH of freshwater when paired with the Rainman Watermaker high output case.
Gasoline Systems are capable of up to
37 GPH

Rainman Watermaker
Pressure Supply Unit (Gasoline PSU)
Two Components – One System
The Rainman Watermaker consists of two components: the Pressure Supply Unit and a set of Reverse Osmosis Membranes. Both are required to make a complete Rainman Watermaker desalination system.Â
The Pressure Supply Unit is easily selected based upon your power supply onboard – so in this case no external would be required, as the system operates from its onboard 50cc honda GXH 50 Engine . The PSU lifts the seawater, filters out dirt and sediment then puts the system under high pressure for operation. A set of membranes are connected to the PSU to extract drinking water from the seawater  – which is the basic operation of the system.

Gasoline Pressure Supply Unit
This system required no external power source, so long as you have fuel. It is ideal if you don’t have a generator and need to conserve your battery bank. Not relying on external power gives maximum flexibility for taking it ashore, loaning it out, or using it in emergency situations.
Details
Technical Specifications
- 2.1 HP Honda GXH50 (4-stroke) engine
- 1/4 Gallon Gasoline = 70 Mins Operation
- 16ft Intake hose with strainerÂ
- Integrated flexible impeller
- 6ft maximum vertical lift above sea level / source water
- GP WMR 316 stainless steel high pressure triplex plunger pumpÂ
- Integrated GP 315SS Ceramic relief valve to prevent overpressurisation.
- Sound level – 73dB at 20ftÂ
- Rotomoulded polypropylene case
- PSU storage / mounting seat included
PSU Dimensions
- PSU Weight 58lbs
- L23.4″ x H17.7″ x D12.2″

Rainman Watermaker
Membrane Options
Two Components – One System

High Output Membranes
26 – 37 GPH
The high output membrane is the flagship model – designed specifically for the Rainman Gasoline  Pressure Supply Units. With the High Output Case, you can expect to produce between 26 – 37 GPH. This is our most popular and highest output option.
Details
- Â Compatible the Gasoline PSU
- Produce Up To 37 Gallons Of Drinking Quality Water Per Hour.
- Desalinate Sea, Brackish and Fresh waterÂ
- Twin 40″ Dupont Filmtec Membranes
- Robust Polyethylene Case
- 10ft Brine Discharge Hose
- 10ft Product Water Hose + 33ft Extension
- 16ft High Pressure hose (PSU connection)
- Length – 46.6″
- Depth – 5.1″
- Height – 9.8″
- Weight – 52lbs
- 2 Year Rainman Warranty
- Preffered Seatask SupportÂ

COMPACT MEMBRANES
13 – 18 GPH
An ideal companion for the Gasoline PSU if you are short on space, and do not require the higher output that the High Output membrane provides. This compact case, together with the Rainman Gasoline PSU is capable of producing between 13 – 18 Gallons Per Hour.
Details
- Compatible with the Gasoline PSU
- Produce Up To 18 Gallons Of Drinking Quality Water Per Hour.
- Desalinate Sea, Brackish and Fresh waterÂ
- Twin 21″ Dupont Filmtec Membranes
- Robust Polyethylene Case
- 10ft Brine Discharge Hose
- 10ft Product Water Hose + 33ft Extension
- 16ft High Pressure hose (PSU connection)
- Length – 27.2″
- Depth – 5.9″
- Height – 8.7″
- Weight – 32lbs
- 2 Year Rainman Warranty
- Preffered Seatask SupportÂ

ECONOMY MEMBRANES
13 – 18 GPH
The most economical companion to the Gasoline PSU. With the Economy Membrane, you can expect production rates between 13 – 18 Gallons Per Hour.
Details
- Compatible with the Gasoline PSU
- Produce Up To 18 Gallons Of Drinking Quality Water Per Hour.
- Desalinate Sea, Brackish and Fresh waterÂ
- 40″ Dupont Filmtec Membrane
- Robust Polyethylene Case
- 10ft Brine Discharge Hose
- 10ft Product Water Hose + 33ft Extension
- 16ft High Pressure hose (PSU connection)
- Length – 46.6″
- Depth – 5.1″
- Height – 9.8″
- Weight – 23lbs
- 2 Year Rainman WarrantyÂ
- Preffered Seatask SupportÂ
FEATURED VIDEO
Thank you to our customers for taking the time to send in and record there experiences with there Rainman Watermakers!
Rugged and Robust
Rainman Watermakers are solid and robust portable desalination systems – designed for the rigors of the maritime environment and built with ingenuity, with the rainman gasoline systems being completely independent, and backed by the global and prestigious Rainman and Honda warranty. Check out the videos below to see out most popular portable desalination systems in action and why you too will love the Rainman Watermaker System.
Less Than 10 Minutes
The Rainman Watermaker – portable configuration – comes ready to operate out of the box. With the first time set up of your portable desalination in as little as 10 minutes, you can benefit from a fully functional, and extremely robust portable desalination system right away – without the cost, downtime or complexity of installation.

Can The Rainman Gasoline System Be Used As A Generator?
No! The rainman gasoline watermaker is powered by a honda engine – which mechanically drives the pumps via a drive belt system – this does not produce electricity, and more importantly, keeps the energy purely mechanical to maximise system efficiency.Â
Do I Have To Buy Spares Through Rainman / Seatask?
No! The Rainman Watermaker system uses components that are compatible with many other brands – and the sizing of the membranes and filters are common size – which means that you can source from various marine stores globally.
What Is The Maintance Required on A Rainman System?
All systems onboard require maintance – your watermaker is no exception. A full guide comes with your system – but as a rule of thumb:
- Â 5-50 Hrs – Prefilter Change
- 1-2 Years – Impeller & Oil Change
- 5-10 Years – Membrane, Packings and drivebelt Change