General considerations

The yachting industry has always been an accelerator for cutting edge technology. In regards to drinking water supply this can only be achieved by purification as close as possible to your tap in a correct setup.

Contrary to domestic solutions where raw water quality is of a more or less consistent quality, extra care has to be taken when the source is a tank. Reverse Osmosis treated seawater (coming from a watermaker) as one source, commonly found on medium sized and large yachts is of superior quality than potable water, yet a variety of minerals, essential to a healthy ph level (alkaline, above 7 ph) and pleasant taste is lost in the process.

Once in the tank, the water is subject to further possible contamination. Temperatures around 25°C provide ideal conditions for divers pathogens (bacteria, viruses, cysts). Further older tanks potentially leak heavy metals into the water, either from non food-grade coatings or its raw material itself.

The water quality provided from mains (tap) connections in port strongly depend on the yachts’ cruising area. Although the mains water will comply in most countries with national potable quality standards it must not be considered safe, healthy and tasty. Besides questionable levels of organic and inorganic matter these sources contain pharmaceutical residues, micro plastics and disinfection by products, causing serious long term heath risks.

Correct treatment:

To produce truly healthy and tasty drinking water several treatment stages have to be considered. A complete solution consists of:


It is crucial for a trustworthy long term solution, providing the correct quality with reasonable maintenance efforts and minimal costs of consumables to chose these four stages accordingly to your needs.

  1. PRE-FILTRATION (aims to protect the purification membrane):
  • Softener

If the raw water source is harder than 10° DH (amount of dissolved Calcium and Magnesium minerals) a softener is required as first part of the pre-filtration. It is recommended to have the softener before the tank, besides protecting the purifiers membrane it prevents calcium scale up throughout your whole piping system, avoids calcium stains in bathrooms, galleys and deck wash-downs and gives a superior sensation under your shower.

This can be a mobile unit with manual regeneration or a fixed installed unit with automated regeneration.

  • Micron filter

A string wound filter element with a pore size of 5 micron is sufficient to eliminate harmful solids.


An activated carbon (AC) filter adsorpts chlorine and eliminates odor and taste.

The micron and AC filter is a standard component of any purifier in our product line. Sizes are available in 5”, 9 3/4”, 20”, provided in a duplex filter housing.

2. PURIFICATION (eliminates contamination to molecular cut off weight of 200Daltons)

To eliminate above discussed contamination, Water without Waste recommends Nano or low RO purification. Technically the same process as found in a watermaker yet on a lower pressure level, sufficient for fresh water.

For a single drinking water outlet a point of use system purifies on demand. All purifiers in our product line have automated flush mechanism and read out the quality of the permeate water.

3. POST-FILTRATION (re-introduces essential minerals)

After the purification process the permeate tends to be slightly acidic (subject to raw water quality) and is chemically tasteless. To have a healthy alkaline ph level above 7 the permeate passes through a cartridge filled with 8 different minerals (Ca, Na, K, Cl, Mg, Fe, Zn, Cr).  According to your water pressure and flow rate the permeate picks up these minerals and becomes healthy & tasty drinking water.

4. DISTRIBUTION (provides volume, chill and sparkles)

  • Taps

All our systems come with a drinking water tap, some of which communicate the water quality and technical status of the purification unit on tap level. If your solution includes a cooler/carbonator device the drinking water is provided by a 3 way tap, distributing purified ambient temp water, chilled water and chilled sparkling water.


  • Volume

Standard Point of Use purifiers have a flow rate between 50 and 100 l/h. To fill up a glass, carafe or re-usable bottle as fast as you would tap your potable water an expansion tank provides a 8L buffer which gives a much better flow rate.

  • Cooler, Cooler/Carbonator

For one’s utmost convenience a cooler or cooler/carbonator completes the onboard drinking water plant. Units which fit the commonly available space on a yachts galley (under the sink and/or galley floorboards) can provide around 25L of chilled water per hour.

  • In addition to the cooling compressor, CO2 can be injected into the icebank. A manual valve lets you adjust the “fizziness” of your sparkling water. Water without Waste recommends re-fillable CO2 bottle (2 l, 4 l ,6 l) though recognizes the difficulties to do so on a moving yacht and offers also disposable cartridges, providing bubbles for 80-120L.