Water Maker: Purchase, Installation & Usage Considerations

We bought a water maker two years ago. As one of the most expensive items on the boat it was a significant purchase decision, but it wasn’t just the cost that had to be considered. In this essay we  discuss the decision-making process involved in a water maker purchase. Also we examine some thoughts on installation and provide an insight into how it is used on board. We round up with some related issues and finish with recommendations, pros and cons.

We hope that this helps anyone looking to purchase a water maker for their boat and we encourage water maker owners to add their own comments at the bottom of the page.


Buying a water maker is a big purchase decision. It is costly, takes up room on the boat and, like anything mechanical, requires maintenance. With these nagging thoughts in mind is it really worth the expense and hassle?

Having kitted out our boat with some long-distance cruising essentials like solar-panels and wind-pilot, we had just enough budget left to buy a water maker. Our plan was to leave Turkey with the Vasco Da Gama rally, which would take us from Turkey to India, a trip of 4,500 miles. Having now completed this trip we hope to continue eastwards on our own. We ended up purchasing a 12v Schenker 30M, which produces 30 litres an hour at a rate of 8amps on a 12v system.

This is how we got to that position:

Here follows a simple analysis of the considerations we deemed necessary before purchase.

Did We Really Need It?
This question was the one we considered the longest. At the time we were based in Turkey and we carry 450 litres of water, so we needed only pull up to a restaurant once every three weeks to fill up. The abundance of both water and restaurants in Turkey negated the need for a water maker. I can say for sure that had we stayed in Turkey we would have spent our money on something else. I’m not so familiar with Greece and have no experience of sailing in the Med but the same rule applies. (That said I did spend two months cruising the Dodecanese on my own, anchoring at every island I visited, and I used the water maker frequently.) As long as one is sure one can get drinking water at the usual places then the need for a water maker is questionable.



Nice restaurant, but can you fill up my water tanks please?



Of course with our proposed route taking us through the Suez Canal and into the Red Sea, the availability of drinking water wasn’t guaranteed. We had it on good authority that beyond Egypt the availability of water becomes scarce. The longest gap between marinas would be Galib in Egypt to Cochin in India, roughly 3,000 miles and any drinking water sourced from ashore would have to be transferred by jerry can. The idea of a water maker suddenly becomes more attractive!

Independence And Convenience
Yotties often boast that being on a boat is being independent, but we still need to get our water from somewhere. Even when drinking water becomes available, it might mean having to spend the night in a marina, or buying an evening meal in a restaurant, e.g. in Orhanye, pictured right. Fair enough, but being able to produce one’s own water really does give one independence. With our 12v solar panel system we would be able to produce water whenever the sun shined, all for free.

12v vs 220v
Esper does not have a generator so a mains-powered 220v water maker was not an option. We could have gone for an engine-driven unit which would have provided the increased levels of water production that a 220v system gives over a 12v system. The idea of running the engine every time we wanted to make water, however, was off-putting. We put aside the idea of an engine-driven water maker. This was perhaps a mistake, which I shall come on to later.

Instead we have 6x40w solar panels. In good sunlight they produce enough power to keep everything topped up and so a 12v water maker running at 8amps was perfectly feasible. With watermaker technology constantly evolving 12v water makers have shed the bad reputation they once had and are now effective, efficient and robust bits of kit.

The Final Purchase
Having made the decision that we would find a water maker very useful, and that it would be 12v, this left a number of options offered by reputable manufacturers. I can’t comment on which one works best as I only know our Schenker. Of the 15 or so boats who took part in the Vasco Da Gama rally, five had water makers. Three had Schenkers and two had Katadyn. They were all 12v systems.


There are many published guides on installing a water maker so I won’t replicate the information here. I’ll just quickly run through some considerations worth bearing in mind.

Do It Yourself
There is one piece of advice I will offer regarding installation of the water maker, and it probably applies to many things on the boat: do it yourself. By installing the water maker yourself you get to know your baby inside out, and believe you me, when the thing stops working you are going to want to know why it’s not playing ball. The only way to gain a proper understanding of its foibles is to install it yourself.

We were lucky in that we used the forward shower and therefore did not need to make additional skin fittings or drastic changes to the boat’s structure. It was fiddly, there was much cursing and it’s in a tight spot, but all filters, cocks and pipes are easily accessible. This is essential for ongoing maintenance.



Half installed, half hidden under the shower seat



Our forward shower had a lifting seat with storage space underneath. Our pump unit and fresh water carbon filter tucked in nicely underneath it, whilst the main unit sits on the slotted shower floor. I adapted the floor so that in case of leaks it drained straight in to the main bilge.

This sounds obvious but install the water maker whilst you have access to spare parts. I know of one person who installed their watermaker whilst traveling through countries where purchasing a high-pressure 16mm hose became a joke! And carry lots of spare parts, including filters and cleaning products.



There is no question that having a water maker vastly improves ones quality of life on board. We all know that being frugal with water is painful, especially if we’re taking frequent dips in the briny sea.

A water maker means being able to shower down properly. It means doing the dishes properly. Hand-washing anyone? Suddenly we’re not washing in salt water but giving our undies the proper clean they deserve. And it’s a real luxury to not have to nag one’s guests about how much water they can use.

Combining With Drinking Water
With the 30 litres an hour and the 450ltrs we carry we’ve found that we use a combination of water maker water and drinking water sourced from ashore. This is quite useful as the mixture means the water continues to taste good and it extends our supply from three weeks to six, minimum. Of course we still take on drinking water from ashore when we can, but we don’t fret about it.

Running Whilst Motoring
On the Vasco Da Gama rally we were often having to motor into prevailing headwinds. Every time the engine was on, we’d run the water maker. Every time we ran the water maker, we’d treat ourselves to hot showers and do hand washing. It’s a real luxury to be in a position where one has to use the water for something because one is making so much of it!


There are no doubt some trade-offs to be made for this luxury. Here are a few worth bearing in mind.

There was a period in the rally when we had days of cloud. It had been a month since we’d plugged in to shore power and our batteries, three year old sealed lead-acid, took a hammering. The unfortunate effect this has on the water maker is that the reverse-osmosis action loses its effectiveness, meaning that it is not filtering out all the salt in the water.

Indeed at a certain point in the rally two of us with the same water maker were convinced that there were issues with the production of the unit as we shared similar symptoms. The common denominator, however, was worn-down house batteries. The fault was not with the unit but with our respective power sources.



Using solar? Make sure you have plenty of this!



This leads me on to the point I made earlier about running an engine-driven unit. In the end we found we were only ever running our watermaker with the engine on as our undercharged batteries were not coping. This was not symptomatic of the water maker, this was a problem with our house batteries. Since we only needed to run the unit for a couple of hours every few days, the concept of having an engine-driven unit suddenly became more practical. Remember an engine-driven unit will produce far more litres per hour than a 12v system. This is perhaps the one consideration that could have affected our purchase decision.

Of course the recommendation in this situation is ensure one has a well-charged and maintained battery bank!

I mentioned that when under-powered, the reverse osmosis action does not work correctly and one runs the risk of contaminating ones water tanks with salty water. There are obvious ways of avoiding this: isolating a water tank for just water maker water; only filling up jerry cans; testing the water every 10 minutes. I installed a number of Y-valves on my port and starboard ‘product’ pipes so that I can switch the produced water to a dedicated ‘taste’ pipe, where I can taste the water at any point to check that it is producing good water.

It states very clearly in the manual: keep your filters clean! A dirty filter is the most common problem with water makers and I can’t emphasise enough how important it is to clean them. One person I know tows their used filters out the back of the boat on the end of a line, which is a good way of cleaning them (this doesn’t work with paper filters over 5 knots as they get shredded!). Filters outside of Europe are dirt cheap so I bought a whole load whilst in Egypt.

One of the myths about water makers is that one has to run them every day to keep them clean. This just isn’t the case. There were a number of occasions when we didn’t run ours for a week. One just has to let the unit run for longer at start-up to ensure it cleans through properly. Bacteria, therefore, becomes more of a concern than dirt. Even so, it is always good practice to clean the unit every few months with the recommended chemicals. Pickling, by the way, is straightforward.


A water maker is only necessary when getting hold of drinking water becomes difficult. It is an expensive purchase and does require maintenance but installed by the boat owner correctly it is not difficult to maintain. It is important, however, to ensure it has a clean filter and the correct voltage supply. Install the unit where spare parts, jubilee clips, hoses and filters are readily available.

Consideration should be given to where the product water ends up, in case the reverse-osmosis stops working effectively and salty water threatens to contaminate the water tanks.

Twelve volt unit technology has vastly improved over the years and are viable options for people who don’t have a generator. A 220v water maker will produce many more litres an hour, as will an engine-driven unit. With this in mind consideration should be given to water consumption, space and budget.


If you are always near a fresh water supply, don’t bother with a water maker. They are expensive and it’s ‘another thing to go wrong on the boat’! Scrap this notion, however, if you want compete independence or are traveling to places where sourcing water is difficult.

If the budget allows and the boat has a generator, get a 220v unit. It will produce more water than you’ll ever need! If you can’t afford it or don’t have a generator, fear not, the 12v systems are excellent. Just ensure you have a well charged battery bank to cope with it.

My last recommendation though is this: given the amount of motoring we had to do, and given that we run our engine at least once every three days when not in a marina, an engine-driven unit may have been the best option. That said, I am very pleased with my 12v Schenker and in 4,500miles we only ever ran out of water once, and that was due to an undercharged battery bank and no sun.


Complete independence
Constant water
Free supply
Easy to use

Expensive to purchase
Fiddly to install
Requires power, be it from solar, batteries or engine
Filters need to be cleaned/changed regularly
Parts possibly difficult to source

If any of you have any experience with water makers and would like to add comments that would help others, please use the comments section below.


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23 thoughts on “Water Maker: Purchase, Installation & Usage Considerations”

  1. Oh dear… sorry to hear you’re having to do that. I was talking with Jim at the London boat show yesterday and he explained the o-rings to us and showed us where they are in that bottom unit (in various sizes if I remember right?) . Like you said, the new models have plastic inserts alongside the o-rings to help protect them. I’ll try to get more info from him on exactly how this differs then. Good luck, and thanks for the info.

  2. Hi Jamie,

    We’re considering a Schenker watermaker; around the same size as the one you have installed.

    I notice you’ve had yours for a few years now. How has the reliability been. Are you still happy with it?

    Happy sailing.


    1. Hi Steve,

      Well, well. Your question couldn’t be better timed! Right now I am attempting to recommission my Schenker and I’m having a few issues. It’s to do with the shaft that moves through the ten O rings in the lower section of the watermaker. I’m having to replace the O rings and it is a royal PITA. However I have it on good authority that the newer versions have done away with this design and gone for something more reliable. That aside, when the watermaker is working, and it worked for us day in, day out, for three years, it is wonderful. Compare the Echotek that draws 19amps to make the same amount of water the energy efficiency of the Schenker is still hard to beat. Check with Jim at Mactra that the new version has this improved feature and you should be laughing.

  3. Regarding cost, I just built a watermaker myself, as many others
    have done before.
    Cost added up to around US 2.000,- including a 12v DC to 230 V AC
    (Europe) inverter, and I know my watermaker. 12 gal/hrs.
    Infos needed ?
    rainerhasse at arcor.de

    1. Thanks, Jeanna, and thank you to all the extra comments too. I recently got in touch with Jim of Mactra, who we purchased our water maker from, and sent him a copy of the article. He was quick to add a couple of pros to a 12v system over a 220v one: the 12v watermakers are quieter than the traditional 220v ones; also if the engine or generator goes down one can’t rely on one’s house batteries to run a 220v water maker.

  4. Bacteria:
    As has been stated a build up of potentially dangerous bacteria can be a potential problem. One simple solution and very cost efective solution to this is to insert a piece of clear pipe between the outflow side of the watermaker and the tank then suspend an ultra violet lamp (12v or 220v) above the clear pipe. The ultra violet light kills the bacteria as the water flows towards the tank and ensures clean drinkable safe water.

  5. David Hatchman

    Hi Guys

    In the eary days of RO systems on long distance yachts it was thought that pure water would depleat the bodies minerals and RO was blammed for many ailments. The latest I have read is that these ideas have been proved to be groundless and the problems crews faced were all down to poor diet. Just like in Cptn Cooks day.

  6. Hi Jamie, Been following your travels,great reading.
    I think for a liveaboard a watermaker is part of the icing on the cake.I installed our’s and concur with your views. It’s good not having go into dedicated ports etc for water if that’s all you need. Just a point about using desal water for drinking, hasn’t the water been stripped of all minerals and in drinking desal water it can strip the body of essential vitamins ?

    1. Hi Graham. Yes, this is true. There was a point in the rally when I was getting hangnails, sores and other irritations that could have been due to lack of nutrients in the water, but then we were in salty conditions for months on end so I’m not sure it was the purified water that was causing those complaints. When I drank the water I was often mixing it with Tang (fruit cordial powder with added vitamins) and where possible I was putting the water maker water it into the water tanks where we had ‘proper’ water taken from ashore, thus mixing the two. I think the point is it won’t kill you and given the choice I’d prefer to have purified sea water rather than none at all!

    1. Hi Charisma. I’m not entirely sure what you mean but I think you are asking why we didn’t cover costs. We made the assumption that anyone in the market for a water maker would already have done some basic research and have a clear understanding of the costs involved. The only additional costs for us covered the piping, Jubilee clips and then filters.

    1. Yeah, they’ve been around for a while but always suffered from a reputation of breaking all the time. The new generation of marine water makers are pretty robust and great to have on board. They are still very expensive though!

  7. David Hatchman

    I have an echotec water maker running on 230v. The 4kva generator gives me more power options power tools, heaters, bat charging, diving compressor etc., than a solar panel and its very cheap to run .3lt per hr.

    A plus point you didnt mention is that water makers produce pure water, you dont need so much detergent or soap to wash and there is no need to rinse surfaces as they dry clean. But most important is that pure water descales all the pipework and fittings including the hot water calorifier extending its life.

    good luck with the rest of your trip

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