A watermaker on board provides some savings in:

  • Time: you don’t have to look for nearby ports to stock up or buy water, not even to drink.
  • Weight and space: it is not necessary to store the water and the reduction of the weight and draught of the boat allows more space for storage or fuel tanks in the case of long trips.
  • Money: it is not necessary to dock in port in high season, you do not have to buy and store water so it reduces the ballast and saves in fuel. In addition there are watermakers with very low electrical consumptions (from 4 Watt/litre).


It also provides:

  • Greater autonomy: not depending on the stored water there will be no need to change the plans to go to port and load water.
  • Greater comfort: water consumption at the end will go beyond the minimum comfort amount.
  • An impact on safety and health by being able to consume water free of bacteria and viruses. For destinations where it is easier to get diseases through water you can also use a UV sterilizer.
  • Possibility of washing the boat with demineralized water without leaving stains.

In general, watermakers are used between 4 to 6 hours a day. In that time, the water used on board comes from the osmosis system.

You can determine the needs of freshwater according to the daily amount required for: drinking, ice, washing of dishes and clothes, showers, cleaning the boat (without leaving marks) and using the WC. If you divide the total quantity of water needed in a day by the amount of hours you want your watermaker to work per day, you will get the gallons per hour that you need your watermaker to produce. For example, if the total amount of water you need per day is 170 gallons and you divide by 5 hours operation then you would require a 34 gallon per hour system. Marine systems have a production range from 7 to 283 gallons per hour of operation (170 to 6800 gallons per day). Commercial systems up to 44000 gallons per day.

  • Water needs: it is better to buy a watermaker that produces more gallons and runs less hours per day (ideally between 4-6 hours) than a small one that we have always in operation.
  • If we want an analogue or electronic watermaker: if we decide on an analogue system we must know that it is more economical because it does not carry electronic, it will be necessary to do the fresh water flush manually using the manual valve and to discriminate if the production of the system is salty or sweet. A manual test should be done to check the salinity and to derive the water to freshwater tank or to derive the water of rejection to the sea. You will need to clean with fresh water and derive the fresh non-saline water to the freshwater tank or derive to sea with a pair of manual valves.
  • If you want a compact or modular watermaker: the space and distribution of other elements in the engine room or compartments will determine our choice. If we do not have too much space, it is always better to choose a modular one, especially in sailboats, as the space is smaller. With the modular we will be able to dispose filters, membranes and motors in spaces that are free of the engine room. If we have enough space it is always easier to install a compact watermaker. A modular watermaker produces the same amount than a compact and the price of both models is the same.
  • The energy supply that we have on board (AC or DC).
  • Energy consumption: a Spectra watermaker with Clark recovery pump consumes from 4 watts/liter. On average, four photovoltaic panels can feed your watermaker (220 watts).
  • It is advisable that membrane containers be of fiber to avoid oxidation and possible damage to the membranes (although the containers are metallic with treatment, the salt of seawater is highly corrosive). The containers must withstand a pressure up to 100 bars.
  • The feed pump must be installed below the waterline to prevent it from working in a vacuum. If this is not possible (for reasons of space, for example), this pump must be self-priming. It is important that the inside of the pump is made of anticorrosive materials with seawater. Internal brass parts of stainless steel or elastomer are usually used to withstand the corrosion of seawater.
  • It is strongly recommended that the high pressure pump be of the highest quality as the Cat pumps or General Pump.

For energy consumption, the watermaker is usually used when the engine is on.

If the watermaker is used between 4 and 6 hours a day we avoid the machine of being subjected to excessive wear of the elements due to excess temperature. If we consider that the watermakers are usually installed in the engine room, with little ventilation, in confined spaces and that usually work in the warmer months, the high pressure pump, which is the heart of the system, overheats past 5 or 6 hours of continuous work. It is advisable that a watermaker works 2 to 3 hours of continuous work twice a day.

Just wait a moment after it is turned on, production is almost immediate.

It can last as long as your boat, up to twenty years, as long as you do the timely maintenance.