PRO Series Watermakers Frequently Asked Questions

What capacity Desalination System is right for my Application?

Water consumption depends on the number of occupants, use of the property and the way the water is consumed. If you currently have any water supply system, you should keep a record of the average water usage as a reference. Keep in mind that once a reliable source of fresh water is available, your water consumption will increase.

If you know your daily water demand, simply divide the amount needed by the hours of power supply available each day or the time you want to run your desalination system each day. The result is the GPH (gallon per hour) rating of the watermaker that best suits your application, e.g., 900 gallons / 3400 liters per day consumption at 6 hours running time requires a watermaker with a capacity of 150 gallons / 568 liters per hour.

Can a Novice install and operate a Desalination System?

On first sight, the possibility to replace costly and troublesome water deliveries and/or avoiding rationing water consumption with “water on command” supplied from your own desalination system may appear economical but challenging for technical novices.

In reality, installing and using a desalinator is exactly as easy as owning a washing machine. All systems are delivered ready for connection to the power supply, feed water, brine return and fresh water line. For a successful installation, simply follow the few steps provided in the comprehensive ECHOTec owner’s manual and read through the information provided on this site.

If you have questions, not answered on this site, email to or speak directly to a desalination specialist; no voice mail, no telephone menus (+868 634 2015, 8:00 – 16:30 North American Eastern Standard Time).

If you prefer to get a turnkey installation, we are happy to provide a complete solution from the layout to commissioning your desalination system.

How much Power do I need to run a Desalination System?

ECHOTec semi-modular desalination systems consume about 2.1 kW for a production of 60 gallons / 227 liters of fresh water per hour. If a generator or inverter is used as the sole power supply or backup, you will need to size it depending on the rating applied at 4.5 to 6 kW to start the system. Once the system runs, you will have ample power available for other equipment or appliances. The system 400 and 700-BHL-1 draws only 1.1 kW at the same power efficiency.

The vertical framed ECHOTec BHL series produces, depending on the model from 38 gallons / 143 liters to 75 gallons / 284 liters per hour and consumes 2.5 kW. The System 3600-DUAL-8 requires 4.6 kW and produces 150 gallons / 568 liters per hour.

All ECHOTec BHL series desalination systems with productions above 1800 GPD are available with optional energy recovery pumps. They can reduce the total power consumption by up to 40%. At an additional equipment cost of approximately 80%, this option may not be feasible where fuel or electricity is available at low cost.

When comparing operating cost, the additional power demand for the essentially higher raw water feed pressure, required for desalination systems equipped with recovery devices needs to be taken in consideration (recovery systems with rotary piston pumps require up to three times the feed pressure needed for conventional plunger pump systems).

The use of energy recovery devices demands finer and therefore more costly pre-filtration to 1 micron compared to 5-10 micron for conventional systems.

Desalination systems with energy recovery devices require electronic control circuits and therefore their use in remote locations without or limited access to factory trained service technicians should be carefully considered.

What is the best Source of Seawater?

Feed water supply is available from seawater (beach) wells and open ocean intakes depending on local regulations, geological conditions and budget.

The horizontal or vertical beach well is the preferred source of feed water as severe weather conditions are less likely to challenge the intake system. The feed water from a well is naturally pre-filtered and “good bacteria” in the sand layers can do their work to further enhance the raw water quality. Where available, a local well drilling company should be consulted to evaluate the feasibility of a seawater well.

However, most domestic or small commercial seawater desalination systems are supplied with raw water from open seawater intakes. Ideally, the desalination system and its feed pump should be located as close and low as possible to the coast line and seawater level. In many cases a centrifugal pump, installed above sea level in combination with a priming reservoir is used to feed the RO system. This allows for easy maintenance of the feed pump and prevents corrosion as the pump can be installed “dry and high”.

Where possible, a removable intake pipe with attached sea strainer should be constructed to allow easy access for the removal of marine growth.

Other than this, there are various possibilities to pump raw water to the pre-filters of the desalination system, all adapted to the conditions of the specific shoreline. You can contact your ECHOTec dealer or to discuss your intake options.

How does a back washable media filter work?

Sand filters or multi-media filters, installed after the feed pump and before the 20 Micron cartridge filter, can be used to prolong pre-filter life and maintenance effort and therefore reduce the filtration cost of a desalination system.

Systems with open seawater intake benefit the most while the water from a sea well, depending on its grade of natural filtration through the sand bed may not require a media filter.

In a conventional sand filter, lighter and finer sand particles are found at the top of the filter bed, and coarser, heavier sand particles remain at the bottom after backwashing. Filtration takes place in the top few inches of the filter bed only.

As the sand or multi-media bed has to be lifted and tumbled for back washing, a fast upwards flow is needed. If the systems feed pump shall be used for the backwash, the diameter or the filter is limited which results in a relatively small diameter of the filtration surface unless an additional larger seawater pump is installed solely for the backwash.

Advanced filter media like Micro-Z, a granular zeolite outperforms conventional media or multimedia materials due to its unique structure, allowing particles to penetrate deeply into the filter bed to provide superior filtration at increased flow rates.

The very low minimum back wash flow requirement of 12-16 GPM/sq. ft., similar to the service flow rate makes this media an ideal, and cost efficient alternative to the multi-media filter as the RO systems feed pump can also be used for backwashing. Standard pool sand filter housings with all plastic valve heads are suitable for the use with Micro-Z in most applications, provided that the filters diameter suites the particular flow requirement of the desalination system.

Can ECHOTec Desalination Systems be powered by Solar or Wind Generators?

Yes. The systems 1800-BHL-4 and 700-BHL-2 are ideally suited to be powered by wind and solar energy. They are available in 115/230V AC to be powered with DC to AC inverters or on special order as 24, 36, 48, 90 or 180 V DC versions.

All ECHOTec BHL series desalination systems with productions of more than 1800 GPD are available with optional energy recovery pumps. They can reduce the total power consumption by up to 40%. At an extra equipment cost of approximately 75%, this option may not be feasible where fuel or electricity is available at reasonable cost.

Also to be considered:

1) Due to continuously decreasing production cost for solar cells, the installation of additional photovoltaic modules may be preferred versus energy recovery systems with their related extra cost and maintenance effort.

2) When comparing operation cost, the additional power demand for the essentially higher raw water feed pressure, required for desalination systems equipped with recovery devises need to be taken in consideration (recovery systems with rotary pumps require up to three times the pressure needed to feed conventional systems).

3) The use of energy recovery devices demands finer and therefore more costly pre-filtration to 1 micron compared to 5-10 micron for conventional systems.

4) Desalination systems with energy recovery devices require complicated electronic control circuits and therefore their use in remote locations without or limited access to factory trained service technician should be carefully considered.

Can a Desalination system be directly powered by a Diesel or Gas Engine?

Yes, on special order engine powered desalination systems are available. This is an interesting option for larger desalination plants as the engine can be used directly to power the high pressure pump without the loss of converting engine revolution to electrical energy and back to pump revolution.

However, most small and medium sized desalination systems in remote locations are powered by generators. This provides AC power for the systems sea water feed pump and other appliances or equipment.  In case of an engine failure or during scheduled maintenance a backup generator can be used.

Will I need a Transfer Pump to lead the Product Water to an elevated Storage Tank?

The product water is pressurized and will flow to a tank above the desalination system.

The back pressure in the product line will reduce the differential pressure needed for the RO process and slightly decreases the output. This should be unnoticed if the tank’s elevation does not exceed about 15m/45’.

To avoid back pressure when the system is not running, you should install a non-return valve in the product line, close to the outlet.

Why should I flush the Membrane Elements after every use?

The fresh water flush is a standard feature on all ECHOTec desalination systems. It exchanges the seawater in the membrane element/s with non-chlorinated fresh water. The simple flushing procedure avoids biological growth due to dying micro organisms contained in the seawater and dissolves mineral build up that may clog the membrane element/s. Repeated every 10 days the fresh water flush also avoids the need for chemical preservation, otherwise to be performed for long-term storage.

Should my Watermaker have an automatic Fresh Water Flush?

The fresh water flush is a useful feature. It exchanges the sea water in your membrane element/s with fresh water and therefore avoids biological growth that will clog the membrane, leading to reduced output and premature failure of the membrane element/s. Repeated every 10 days, it avoids the need for chemical preservation, usually performed for long-term storage.

The main advantage of the automatic fresh water flush is that it will repeat the flush during your absence, often at a user selectable interval. However, if you leave your boat unattended you must turn off the main battery switch; primarily to exclude the chance of an electrical fire, the most common cause for lost boats together with galley fires! Now, when you need it the most, the automatic fresh water flush will not work as it relies on DC power. In addition, you would always need to leave your entire fresh water plumbing under pressure – not a good idea when your boat is unattended.
Bilge pumps should be directly connected to the batteries. There are divided opinions whether the pumps should be fused or not.

For your peace of mind, disconnect your batteries and perform the easy chemical preservation procedure if you leave your boat for more than 10 days. The widely available preservative Sodium metabisulfite “pickles” your system for up to 12 months. All ECHOTec systems are supplied with enough preservative for three long term storages.

Is watermaker product safe to drink?

Provided the membrane element is in good condition, it “filters” to about 0.0005 micron. Virus (0.01 to 0.04 micron) or bacteria (0.1 to 15 micron) will not pass and in reality, waterborne diseases on board vessels using only desalinated water are un-heard of.

However, the condition of the vessels storage tank(s) and/or plumbing can be a concern and should be sterilized e.g.:
with chlorine on commissioning of the desalination system and as an occasional routine maintenance. The desalination system should not be operated in chemically contaminated waters, as the RO process will not safely remove all chemicals.

Active carbon filters after the tank and before the faucet are useful to remove chlorine from shore water but do not improve the watermaker product quality.

Another important consideration is the TDS level (the combined content of all inorganic and organic substances) in the product water. Depending on agency and location, the upper limit for safe drinking water is set to 500 – 1000 ppmTDS.

Drinking Water Regulations:

Can I feed my Desalination System with Brackish or Fresh Water?

Yes, the ECHOTec BHL Series allows you to regulate the operating pressure in order to process any feed water from wells with changing salinity to seawater in the Red Sea.

What is the effect of seawater temperature on the fresh water production rate?

The fresh water output of most desalination systems is rated at a seawater feed temperature of 26˚Celsius or 78˚ Fahrenheit. Membrane productivity, however, is sensitive to changes in feedwater temperature. As water temperature changes, water flux changes almost linearly, due primarily to the diffusion rate of water through the RO membrane.

As a rule of thumb, membrane capacity changes about 2% per degree Celsius water temperature. At very low feed temperatures, pre-heating of the feedwater may be considered. A commonly used method of pre-heating is mixing part of the engines/generators seawater cooling return with the cold seawater, ideally to a temperature of 30˚ Celsius or 86˚ Fahrenheit.

How loud are ECHOTec Desalination Systems?

An important consideration in the choice of the right desalination system is the amount of airborne noise transmitted by the high pressure pump.

Rotary piston pumps run at very high speeds and create a loud pitching noise. Even so more advanced systems with rotary piston pumps have full sound enclosures, they are not suitable for installations close to inhabited buildings.

Plunger or piston pumps are considerable less noisy and create lower frequencies as they run at low RPM.
The ECHOTec triplex plunger pumps are the quietest high pressure pumps in the world.
They are about 10 dB quieter than other brands on the market.

Where can I purchase Consumables?

Other than most competitor brands, ECHOTec watermakers do not require proprietary consumables.
All pre-filter housings and pressure vessels are built to standard sizes in order to allow replacement with widely available spare elements to meet the given system specifications.

Slogans like: “consumables are manufactured exclusively to more demanding requirements and higher specifications” may indicate that this manufacturer’s product requires the purchase of proprietary spares and consumables at drastically elevated prices, only to meet the given system specifications.

The pH buffer/hardener post treatment system is developed by ECHOTec and replacement cartridges are presently not available anywhere else.

All ECHOTec spares and consumables are also available for same day shipping from

Can I clean the Pre-Filter Elements?

Yes. The pre-filter elements can be cleaned several times before you have to replace them.

You should use only pleated polyester pre-filter elements at the micron rating specified in the owner’s manual. String wound or fiber type filter elements cannot be cleaned, have a ten times lower dirt-holding capacity and therefore are not cost efficient. Household under-the-sink filter elements are made from the wrong material; they will fall apart in seawater which will cause fouling and damage to the membrane elements.

Is an Oil-Water Separator needed for my Installation?

When there is the risk of getting oil into the RO system, an oil-water separator (oil absorbing filter) can be installed in the intake line. These filters are quite expensive to exchange, often proprietary and should only be considered when absolutely needed. Remember, oil floats on water and will hardly enter the submerged intake unless feed water is drawn from turbulent water close to a contaminated surface.

Non-proprietary oil-water separators in a multitude of flow requirements are available as optional equipment if needed.

What is the Life Expectancy of an ECHOTec Watermaker System?

With proper maintenance, the life expectancy is more than 20 years.

How can I protect my desalination system against freezing?

If freezing temperatures are expected, you need to protect your watermaker by adding food grade Propylene Glycol to the biocide (storage solution). Both products are infused via the systems service valve.

Will I need any post-filtration of the fresh water (before the water is used)?

Product water from any RO watermaker is extremely pure, has little salt content, is very soft and acidic due to the removal of alkaline mineral constituents of the seawater. Therefore, similar to rainwater, using RO product requires significantly more fresh water to rinse off soap, shampoo and other detergents.

ECHOTec is the first watermaker manufacturer to combat this problem by improving the RO product quality with a standard supplied post treatment system. The newly developed mineral dispenser returns some hardness to the water and offers a practical, low maintenance solution that saves up to 50% fresh water.

The ECHOTec post treatment element also contains a mixture of minerals that returns bicarbonate alkalinity, correcting pH only enough to reach a neutral equilibrium. This dramatically reduces corrosion on metal tanks, boilers, washing machines and plumbing due to acidic product water.

As the water is slightly re-mineralized, this will also improve the taste of the product water.

The vertical framed system does not fit my installation space but I like the continuous duty version.
Can I get a modular system with continuous duty high-pressure pump system?

Yes. For installations where space is limited, the high-pressure pump, the flow/electrical control unit, the pressure vessel rack and the pre-filters of the continuous duty, framed vertical mount system can be ordered in separate modules at no extra charge.
View configuration:

Why choose an ECHOTec Watermaker?

Beacause it Works and Works and Works.


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