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The Art of Making Water: Inside the World of Watermakers

The Art of Making Water: Inside the World of Watermakers

Long ago as a kid on my grandparent’s boat, I remember being fascinated by the watermaker. When low on water, they would fire up this machine that I never saw but could hear pumping away below the deck. At the time, I had no idea what it was doing, but in my adult life, I have become. quite well acquainted with off-grid water systems. And this is where watermakers are needed.

Today, we’ll dive into this industry and examine how a watermaker works, the different types and how they can make the off-grid life easier.

How A Watermaker Works (Explained in 5min) *SeaWater Pro Watermaker Installed On A Sailboat*

What Is a Watermaker?

The name watermaker is a bit of a misnomer as they don’t actually “Make” water. The only way to make water is with a chemical reaction. The most famous of which is simply burning hydrogen gas. 2H2+02 = 2H20. No carbon, no other harmful gasses, and the reason hydrogen is a clean fuel source. But I digress.

Watermakers or water generators mainly take water from a source that is undrinkable and make it drinkable. The two primary types of water generators are reverse osmosis (RO), and atmospheric generators.

Sometimes on boats, these RO units are called desalinators or desalination units. It removes the salt from ocean water so boaters can enjoy potable water.

Atmospheric generators suck water out of the air and turn it into drinkable water. While technically a watermaker, the term typically refers to the RO units installed on boats. Because of this, we will focus the rest of this article on boat watermakers and save atmospheric generators for another article.

Types of Watermakers

There are several types of watermakers. Some require electricity, which you can generate from the boat’s battery bank, engine, or AC generator. High-pressure pump watermakers can produce water quickly but require ample energy.

On the other hand, energy recovery devices (ERD) use a lower-pressure pump, which requires less energy but has more moving parts with pistons to create the high pressure necessary to discharge the portable water. More complexity, however, means ERDs are more expensive and prone to breakdowns.

Other watermakers are portable and you can power them by a hand pump. These produce far less water but are also less expensive. They’re typically best to reserve for an emergency.

Boat watermaker
A watermaker is essential to have on board for safe drinking water.

What Are the Parts Of a Watermaker?

A water maker is a simple machine with some complex engineering. There are several filters and pumps that remove basic dirt and grime. But the most critical part of a watermaker is the semi-permeable membrane that strips out the salt and other contaminants. This membrane is more than a filter, as water molecules are all that pass through. However, there must be high pressure to separate the water molecules from everything else.

Pro Tip: Stay safe while boating by discovering The Most Common Causes Of Falling Overboard Boats.

How Does a Watermaker Work?

Each type will operate differently, but generally, a water maker applies high pressure to salt water to force it through a special semi-permeable membrane. A feed pump typically sucks in saltwater, which goes through a filter first. Next, clean water slowly seeps through the membrane with the help of a pressure pump. This results in fresh, potable drinking water.

Water Maker Parts

Different models and brands of watermakers might have variations in their components and system design. However, most have a similar design and common components. Here are the main parts of a watermaker system.

diagram of water maker

1. Intake Pump

The intake pump is responsible for drawing seawater into the watermaker system. It typically consists of a strainer, which filters out large debris from the seawater, and a hose, which transports the seawater to the system, ensuring a steady supply of water to be processed. These are generally low pressure and intended just as a lift pump.

2. Prefiltration System

The prefiltration system is designed to remove particulates and sediments from the seawater before it reaches the reverse osmosis membrane. This system usually includes prefilters, which trap larger particles, and a sediment filter, which removes smaller particles and sediments to protect the membrane from clogging or damage.

3. High-Pressure Pump

The high-pressure pump plays a crucial role in pressurizing the seawater, forcing it through the reverse osmosis membrane. It includes a motor that drives the pump and a pressure gauge that monitors the pressure of the seawater, ensuring it is at the optimal level for the desalination process. These pumps are generally operated on mains voltage and require an inverter or generator to be running as they draw a lot of power.

4. Reverse Osmosis (RO) Membrane

The RO membrane is the heart of the watermaker, separating salt and impurities from the water. The membrane is housed within a membrane housing and is semi-permeable, allowing only water molecules to pass through while rejecting salts and impurities. The rejected water is concentrated salt water and called brine.

5. Post-Filtration System

The post-filtration system further purifies the water after it has passed through the RO membrane. This often involves a carbon filter, which removes any remaining impurities and improves the taste of the water, and optionally, a UV sterilizer, which can kill any remaining bacteria and viruses, ensuring the water is safe to drink.

6. Fresh Water Flush System

The fresh water flush system is designed to clean and preserve the RO membrane by flushing it with fresh water. This system typically comes off the main fresh tank and valves control the flow of fresh water through the membrane, preventing biological fouling and mineral deposits. The fresh flush discharges out the brine.

7. Controller and Control Panel

The system controller monitors all aspects of the system and turns pumps on and off according to needed safe operation.

The control panel allows users to manage and monitor the operation of the watermaker. It usually features switches that turn the system on/off and control various stages of operation, as well as indicators that display system status, such as pressure, flow rate, and water quality, ensuring the system operates efficiently.

8. Water Storage

The water storage is typically the same tank used for water storage from any source. This tank connects to the rest of the water system via pumps. Because the water production through the RO is slow it takes time to accumulate water and a tank is required.

9. Brine Discharge

The brine discharge component is responsible for expelling the concentrated saltwater (brine) byproduct that results from the desalination process. It typically includes a discharge hose, which carries the brine away from the system, and an outlet, which releases the brine back into the sea, ensuring no build-up of waste within the system.

Additional Components

  • Pressure Regulator: Ensures consistent pressure throughout the system.
  • Flow Meter: Monitors the rate of water production.
  • Salinity Probe: Checks the salt content of the produced water.
catameran sailboat at dock
watermakers are generally found on larger liveaboard boats and cruising boats

How Much Water Can a Watermaker Produce?

An ERD watermaker will produce 20-60 liters of potable water per hour. Remember, this is the lower-pressure option that requires less energy. A high-pressure unit will use two or three times the power but produce 60 liters or more an hour. The water is more free-flowing with a high-pressure unit but will draw 500 watts or more.

Why Would You Need a Watermaker?

Having your clean water supply is critical when boating. Water is heavy, weighing about eight pounds per gallon. So you don’t want to lug around tanks full of water. Making water as necessary means less weight to tote around, which also leads to better fuel economy. Whether you need clean water to wash dishes, cook, or shower, a watermaker can provide for your needs while at sea.

Can a Watermaker Sit for a Long Period Of Time?

You should use watermakers frequently to keep bacterial growth down. You’ll need to flush them out if they sit for longer than a few days. Some watermakers will have automatic controls, while others require you to clean them manually. If you don’t use your water maker often, you must be careful about bacteria growing in the membrane. Flushing with biocide will prevent this from happening and can be a way to store the syetm for a longer period of time.

Drinking potable water on boat
Instead of lugging around tanks of heavy water, use a water maker to lighten your load.

7 Top Watermaker Brands

If you’re looking for a watermaker, there are a few things to consider. Think about the noise level, energy efficiency, and space requirement. Once you’ve decided on a type of watermaker that’s best for your needs, you can choose from these seven top brands.

Rainman Watermakers

In 2014, the first Rainman water maker prototype debuted at a boat show in Australia. This water maker was simple, eliminating electronics and control systems that cause many maintenance problems. Today, Rainman manufactures AC electric, 12VDC electric, and gasoline-powered watermakers. They’re all reverse osmosis units, and even though the Rainman watermakers were initially designed to be portable, the company now offers installed options.


Spectra has been in the water-making industry since the 1990s and was the first to launch the Clark Pump for small-scale desalination. The company offers watermakers for all boaters, from hand-operated desalinators to a 20,000-gallon per day system. If you want to ensure you’ll be taken care of after the purchase, Spectra has an excellent reputation. The company offers rebuild kits to help repair watermakers so owners don’t have to return the entire unit to the manufacturer. 

Sea Recovery

Based in the Netherlands, Sea Recovery has the largest worldwide market share in the water-making industry. The company has been around for over 30 years, using reverse osmosis to provide clean drinking water. It has a worldwide presence with over 200 exclusive distributors. Sea Recovery has watermakers for small yachts up to large cruise ships. The Aqua Mini Pro can produce up to 2,850 liters daily, while the North Sea system can produce almost 200,000 liters daily.

Filtered water
Sail the seven seas with a watermaker in tow.

Village Marine

Village Marine is under the Parker umbrella of products. It has assisted NASA and FEMA with disaster relief efforts but also makes watermakers that are best for commercial use. The main design is for continuous use, but they also have watermakers for partial use depending on your vessel’s requirements. Their models have a range of output and can generate 400 to 2,000 gallons daily. 


Dating to 1998, Schenker owns four patents in energy-efficient products. What began in Italy now stretches around the world to 34 countries. The company uses low-pressure pumps to reduce power consumption by up to 80%. Schenker offers three models with varying capacities. The Wiki is a portable, lightweight plug-and-play watermaker. Zen is a compact, ultra-flat watermaker, and the Smart is an affordable, simple watermaker with straightforward maintenance. Schenker also has seven Modular watermakers for large outputs.


Another Italian company, Osmosea, has been in the water-making industry for over a decade. The company manufactures watermakers for vessels from small boats to super yachts. There are two DC-powered units and three AC-powered units. The smallest unit, the NEW12S, produces up to 25 liters per hour and consumes about 120 watts. The largest unit, the MEGA 2000, produces up to 2,000 liters per hour and requires 18kW.


Echotec has a wide range of products, including modular AC, DC, and belt-driven watermakers. Its products range from a production of 32 liters hourly to self-contained desalination systems with a production of 53,000 liters daily. Echotec claims to have a unique pH buffer element to protect tanks, heaters, and fittings. Dealers are worldwide, from North America, Europe, the Caribbean, and Australia.

Pro Tip: Do you know The Connection Between RVs and Pontoon Boat Brands? It may surprise you!

How to make Water on a Sailboat (and how to Build your own Watermaker) - 4 years later review

The Modern Technology of Watermakers Has Changed Boating

You no longer have to load down your boat with days worth of water in your tanks. Investing in a watermaker allows you to enjoy more fuel-efficient sailing and space for long-term adventures. It will take some research to decide which watermaker is right for you, but with so many options, you won’t feel pigeonholed into a wrong decision. Modern technology has truly changed boating!

Which watermaker would work best for your next adventure? Tell us your thoughts in the comments!

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About Mortons on the Move

Tom & Caitlin Morton of Mortons on the Move gave up the stationary life for one where they are constantly on the move. They are full-time travelers, television hosts, and digital media producers.
They left their jobs, sold their house and possessions, and hit the road in September 2015 in their full-time “home on wheels”. Since then they have traveled the US, Canada, and even internationally by RV.
Now, they are Discovery Channel & PBS TV Co-stars of “Go North” on Amazon Prime Video, co-founders and instructors of RV Masterclass, and contributing authors for and an Arizona travel guide.

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