Rainman AC (Electric) Water Maker


The AC system is by far our most popular watermaker. It’s a very simple and highly reliable system that can make up to 140 litres (37 gallons) of fresh potable water per hour.

Options exist for this system to be run as portable without any plumbing or plumbed in with a minimum footprint installation.

Our AC system is a great option when you want to make a lot of water quickly and get back to enjoying yourself.

ac electric water maker
ac electric watermakers

Two Components – One Watermaker

The system is made up of a pressure supply unit (PSU) and a reverse osmosis unit (RO).

Both parts are required to make a complete watermaker. The PSU lifts the seawater, filters out the sediment and puts the system under high pressure, while the RO unit extracts fresh water from the stream of pressurised seawater.

Most of the water goes out to waste as brine output, while about 20% of the volume is extracted as fresh potable water for your tanks.

Different RO options exist for you to select with your AC Rainman system, each to achieve their own specific objective.

buy water maker florida usa


With recent advancements in generators, batteries, and solar power generation, you have several options for powering the AC system.

Originally designed to run off of a minimum of a Honda 2kW generator, it will be easily powered by your inbuilt generator or a quality 2kVA inverter.

Choose either a 230VAC/50Hz or 115VAC/60Hz option to suit the power available in your situation.

electric watermaker
installed electric watermaker

Installed or Portable Watermaker

Our traditional system in the blue case can be used as either portable or installed. If you wish to install it, it becomes a two box installation. Various approaches that can be utilised include:

  • Keep it portable, pulling it out and setting it up each time you wish to use it.
  • Leave the unit in a locker, but pull out the hoses and throw overboard to make water, avoiding the need to move the system around on your deck.
  • Keep the system portable, but use a cam-lock fitting to temporarily plumb the system into a teed deck wash fitting. This gives the benefits of an installed system while using your portable unit while underway.
  • Fully plumb the system in, including the autoflush system.
rainman watermaker ac installed pickle bucket

Video Demonstration

Brief demonstration to show routine operation of the portable Rainman system.

Reverse Osmosis Options

You have three basic reverse osmosis (RO) options, depending on your water requirements, space available, and budget.

All three RO options are compatible with the AC PSU and available in either the Portable and Modular configurations.

More information about reverse osmosis »

desalination reverse osmosis

Portable or Installed Modular

The system can be purchased either as the traditional blue case version or in the Modular configuration. The performance and power consumption are identical between the two options, so your specific requirements control which is best suited for your application. The table summarises the differences between the two options.

portable watermaker
rainman watermaker naked

Features common to both Portable and Modular versions

1.5 HP totally enclosed fan cooled (TEFC) induction motor
1250 watts steady state power consumption
Current draw 6 amps (230VAC) or 12 amps (115VAC)
Power cord length: 3 metres (10 ft)
Plug type choices: US (NEMA 5-15), Australian (AS/NZS 3112), UK (BS 1363), Europe (CEE 7/7)
Integrated flexible impeller lift pump uses non-proprietary impeller
2 metre (6 ft) maximum lift above sea level
General Pump WMR 316 stainless steel high pressure triplex plungerpump
Integrated General Pump 316SS/ceramic relief valve to prevent overpressurisation
3 metre (10 ft) LDPE food grade product water hose, with 10 metre (33 ft) extension (8mm OD)
Sound levels – 62dB at 6 metres (20 ft) – see chart

Portable version specific features

Modular version specific features

Case of sturdy injection moulded polypropylene No shell
PSU storage/mounting seat: fibreglass reinforced nylon with strap PSU easy mounting kit: fibreglass reinforced nylon for high rigidity and tensile strength
RO Case (mountable if desired): rotomoulded polyethylene RO easy mounting kit: fibreglass reinforced nylon for high rigidity and tensile strength
Plumbing installation kit at extra cost Plumbing installation kit included with purchase
Single 10″ x 2.5″ non-proprietary 5 micron prefilter to remove sediment mounted on PSU Single 10″ x 2.5″ non-proprietary 5 micron prefilter to remove sediment with SS316 mounting bracket
0 – 150lph (40gph) product water flow meter, integrated into RO case 0 – 150lph (40gph) product water flow meter, with SS316 mounting bracket
Valve/gauge control assembly integrated into RO case Valve/gauge control assembly at end of 5 metre (16 ft) high pressure hose for remote mounting
5 metre (16 ft) intake hose (1/2″ ID) fitted with one way valve to remain primed, with detachable strainer 5 metre (16 ft) intake hose (1/2″ ID)
3 metre (10 ft) brine waste discharge hose (10mm OD) 6 metre (20 ft) brine waste discharge hose (10mm OD)
PSU weight: 24kg (53lb) PSU weight: 23kg (51lb)
PSU Dimensions: 600 x 375 x 270mm (23.6 x 14.8 x 10.6″) PSU Dimensions: 470 x 270 x 240mm (18.5 x 10.7 x 9.5″)
Related RO weight
– High Output: 23kg (51lb)
– Compact: 14kg (31lb)
– Economy: 11kg (24lb)
Related RO weight
– High Output: 22kg (49lb)
– Compact: 13kg (29lb)
– Economy: 10kg (22lb)
Related RO dimensions
High Output: 1,180 x 250 x 130mm (46.5 x 9.8 x 5.1″)
Compact: 690 x 220 x 150mm (27.2 x 8.7 x 5.9″)
Economy: 1,180 x 250 x 130mm (46.5 x 9.8 x 5.1″)
Related RO dimensions (in mounting brackets)
High Output: 1,170 x 220 x 120mm (46.0 x 8.7 x 4.7″)
Compact: 670 x 220 x 120mm (26.4 x 8.7 x 4.7″)
Economy: 1,170 x 220 x 120mm (46.0 x 8.7 x 4.7″)
rainman control panel watermaker

Control Panel

The optional control panel provides a remote management capability for your installed Rainman watermaker. It’s a highly presentable and functional add-on component that will enhance your Rainman user experience. 

It is an injection moulded ASA acrylic panel that remains true to Rainman’s reputation of elegant simplicity. 

  • Integration with the Rainman autoflush system, triggers flush cycle after powering the watermaker off.
  • Built in tri-colour LED salinity sensor indicates when water is good to route to your tank.
  • Can be installed flush mounted, standalone with the included enclosure box, or even externally with the optional hatch.
  • Simple installation with no high pressure fittings or high voltage wiring.
  • Backwards compatible if you already have an installed electric modular or portable Rainman.

More information about the Rainman control panel »

rainman watermaker control panel


Your Rainman watermaker is a very robust piece of equipment, but caring for certain aspects will prolong its life. Regularly flushing your Rainman with fresh water will maximise the life of your watermaker membranes.

The optional autoflush system incorporates a solid state programmable timer that will flush your Rainman watermaker after each use and every seven days thereafter. It incorporates built in protection if your boat loses power during or between flush cycles.

More information about the Rainman autoflush system »

rainman autoflush countdown timer
rainman watermaker 12 volt accessories

Optional Accessories

While the base system will be sufficient for many customers, a number of options are available to get more out of your Rainman watermaker.

  • The plumbing installation kit is included with the Modular Rainman systems, but can also be a very useful option if you plan to install your Portable Rainman units.
  • A hydrotester will give you indication of the total dissolved solids (TDS) so you can know how your membranes are ageing.

Rainman desalinator optional accessories »

battery desalinator 12v

Spares and Consumables

Your new Rainman system will arrive with enough spares and consumables to keep you going for a while, so most customers do not need to order more with initial purchase. There are a variety of items you will need over time to keep your system running for many years.

Rainman Watermaker spare parts and consumables »

rainman watermaker spare parts

AC Watermaker System Options Gallery

rainman watermakers electric model psu case
Portable PSU

230VAC or 115VAC

rainman watermakers electric case reverse osmosis
Portable 140L RO

2 x 40″ Membranes

rainman watermakers electric compact reverse osmosis case
Portable 70L RO

2 x 21″ Membranes

rainman watermakers electric reverse osmosis economy case
Portable 75L RO

1 x 40″ Membrane

rainman pressure supply unit naked
Modular PSU

230VAC or 115VAC

rainman installed electric watermaker reverse osmosis high output
Modular 140L RO

2 x 40″ Membranes

rainman installed electric watermaker reverse osmosis compact
Modular 70L RO

2 x 21″ Membranes

rainman installed electric watermaker reverse osmosis economy
Modular 75L RO

1 x 40″ Membrane