DIY Watermaker Guide: How to Build Your Own System for Clean, Drinkable Water


We all know how vital clean, drinkable fresh water is for survival. But what if you could take matters into your own hands and learn how to make your own system of clean fresh water with a DIY Watermaker? Imagine having access to unlimited, drinkable water from the comfort of your own home. With the right materials and components, you can create a DIY Watermaker that will provide you with clean water for years to come. In this guide, we’ll cover all the necessary steps to build your very own DIY Watermaker System – from researching potential costs savings and gathering materials to testing and maintenance tips. With this guide in hand, you can have access to safe drinking water anytime, anywhere. So let’s get started!

What is a Watermaker?

I remember the first time I heard about a watermaker. I was boating with friends, and someone had  one of these seemingly magical contraptions. It looked like a small, portable water maker that could turn saltwater into drinking water. I was amazed—and even more so when they told me it was a DIY project! While it seemed daunting at first, it didn’t take long to realize just how easy and rewarding a DIY Watermaker project can be. And the cost saving compared to buying an off the self system makes this the cheapest option available

A Watermaker is simply a device that uses reverse osmosis technology to filter out salt and other contaminants from salt water or fresh water, leaving you with clean, drinkable water. It works by pushing the source water through a series of filters and membranes that remove impurities before storing the filtered product in a container for later use. Building your own system isn’t as complicated as it might seem—all you need are the right materials and components, some patience, and this guide to get started!

A watermaker has four main components. These are a seawater intake, a high-pressure pump, a reverse osmosis membrane, and a freshwater output. The seawater intake filters out large debris or particles. The high-pressure pump forces the seawater through the reverse osmosis membrane. The reverse osmosis membrane removes impurities from the seawater. The fresh water output stores clean, drinkable water.

Before beginning, it’s important to consider if there is sufficient power available for a water maker, as it consumes a significant amount of electricity. It may be necessary to ensure there are enough solar panels and lithium batteries to handle the load, particularly on smaller boats where adding additional solar panels may not be feasible.

Buy vs DIY Watermaker Build

When considering whether to purchase or construct a watermaker, it is important to acknowledge that both options have advantages and disadvantages. Determining which option is best for you will depend on factors such as budget, technical ability, and water usage requirements.

When contemplating building a watermaker, it is important to possess technical knowledge and DIY skills. While constructing a watermaker can be satisfying, it can also be laborious and difficult. Conversely, purchasing a watermaker is a convenient way to obtain a high-quality product, but it may be expensive.

Here are some of the pros and cons to consider before choosing what path you should take:

Buying a watermaker:


  • Convenience: Buying a watermaker means you don’t have to spend time designing, sourcing parts, and building it yourself.
  • Quality: Off-the-shelf watermakers are usually designed and manufactured by experienced companies, ensuring that you get a reliable and high-quality product.
  • Warranty: Buying a watermaker typically comes with a warranty or guarantee, providing added protection and peace of mind.
  • Availability of parts and support: In case of maintenance or repairs, it is often easier to find replacement parts and support for a commercially available watermaker.


  • Expense: As mentioned earlier, watermakers can be expensive, and this is especially true if you want a high-quality, high-capacity unit.
  • Customization: With a pre-built watermaker, you may have limited options to customize the unit to your specific needs.
Building your own watermaker:


  • Cost: Building your own watermaker can save you a lot of money, especially if you use readily available materials and components.
  • Customization: Building your own watermaker allows you to tailor the unit to your specific needs, such as capacity, energy consumption, and other factors.
  • Satisfaction: Building your own watermaker can be a rewarding experience, providing a sense of accomplishment and pride in your creation.


  • Time and effort: Building your own watermaker can be a time-consuming and challenging process, especially if you don’t have prior experience in DIY projects.
  • Quality: Depending on your technical skills, the quality of the unit you build may not be on par with commercially available watermakers, which could lead to maintenance and reliability issues.
  • Warranty and support: If you build your own watermaker, you won’t have the same level of support and warranty that you would get with a pre-built unit.

Buying a watermaker

This post is not about buying an off the shelf watermaker, but I decided to include a list of some commonly available watermakers out there just in case you want to explore that option.
Schenker Watermakers
QuenchSea (here is a post about the QuenchSea)

Build a DIY Watermaker

Building a DIY watermaker is a challenging task that requires technical knowledge and expertise. However, it’s doable with the right tools and materials. Research is crucial, and it should be given more attention than you think you need. Mistakes can be costly as the parts are expensive. Try finding as many DIY YouTube videos and guides as possible, and I’ve listed a few at the bottom of the page. It highly recommended to check your watermaker design multiple times before you start the build.
I have listed a few of them at the bottom of the page.

Step 1: Conduct extensive research

Research is crucial. Incorrect measurements can cause parts to not fit during installation. Compatibility of all parts is also important. Avoid selecting the wrong size for connectors by taking your time and not rushing.

DIY Watermaker

Step 2: Acquire ALL parts required

Before beginning installation, ensure that all necessary parts have been received. If a part is on backorder, it may be out of production, requiring a system redesign. Unopened items are easier to return. Conduct a dry fit to confirm all parts fit together. Below is a list of required components.

Here is a basic list of the components you will need:

  • A high-pressure pump (60-70 bar, 900-1000 PSI)
    A low-preasure pump (optional, but recommended)
  • A reverse osmosis membrane with housing
  • A pre-filter housing + filers
  • A post-filter housing (optional)
  • A pressure gauge
  • Tubing and fittings
  • A freshwater tank
  • A seawater intake/seacock
  • A 3-way valve
  • A Brine water outlet

Step 3: Install the Seawater Intake/seacock

To install the seawater intake, start with a through-hull fitting. This allows seawater to enter the watermaker. Drill a hole in the boat’s hull and install the fitting. Connect the intake to the pre-filter housing using tubing and fittings. It’s a good idea to use a seacock that can be closed or install a cut-off valve after the intake.

Step 4: Install the sea strainer

Getting a sea strainer is optional, but recommended. It’s a prefilter that removes larger items from the water. Adding filters increases system stability and functionality, and lowers maintenance costs as a bonus.

Step 5: Install the low-preasure pump

Using a priming pump is recommended, but not necessary. It ensures enough water is delivered to the high-pressure pump. If you decide not to install it, place the pump near the intake and avoid installing it higher than the seawater intake. Installing it too high will cause problems.

Step 6: installing pre-filtration units

To properly install the pre-filtration units, it is recommended to place the 20 micron filter in the first unit and the 5 micron filter in the second unit. It is acceptable to mount the filtration units above the low pressure pump, provided the distance is not too great. If the units need to be installed more than 1m above the pump, a larger pump may be necessary.

Step 7: Install the High-Pressure Pump

The reverse osmosis membrane is a crucial component of the watermaker, as it eliminates salt and other impurities from seawater. It can be installed in a housing and connected to a high-pressure pump using tubing and fittings.

Step 8: Install the Reverse Osmosis Membrane

The reverse osmosis membrane is a crucial component of the watermaker, as it eliminates salt and other impurities from seawater. It can be installed in a housing and connected to a high-pressure pump using tubing and fittings.

Step 9: Install the Pressure Gauge and Control Panel

One option to consider is installing a pressure gauge to track water pressure within the system. Another possibility is the installation of a control panel, which can provide monitoring and control of the watermaker. However, it should be noted that this component can be costly, and may be omitted in some DIY projects.

Step 10: Connect to water tank and testing valve

The membrane has two outlets on its back. We must connect the fresh water outlet to the water tank, but a 3-way valve needs to be installed in-between. This is necessary to discard the first portion of water during start-up of the watermaker. More details will be covered in the “Use section.”

Step 11: Electrical installation.

The final step is to connect the pumps with appropriate wires and fuses. Please ensure proper selection.

Installation Video

As soon as I have received all parts and completed the install I will post my installation video here.

How to use your watermaker

This is a concise tutorial for utilizing a watermaker.

  1. To ensure the removal of any saltwater in the system, activate the watermaker and allow it to run for a few minutes.
  2. To operate the watermaker, simply open the intake valve to allow seawater into the system. The watermaker will effectively remove any impurities from the seawater.
  3. To produce drinkable water, the filtered seawater must be forced through a reverse osmosis membrane using a high-pressure pump, which eliminates salt and other contaminants.
  4. Gather fresh water in a container that is clean.
  5. After using the watermaker, it is recommended to flush the system with fresh water to eliminate any remaining salt or impurities.

When using a watermaker, it is important to adhere to the instructions provided by the manufacturer. It is also recommended to regularly check and replace filters and membranes as needed to optimize the performance of the watermaker, as different models may have varying procedures.

My partslist

Here is a list of items i plan to use for my install. Please note that some of the links are affiliate links and I might receive a commission if you use them to complete a purchase.

List and prices updated on March 16, 2023

Pumptec 116C-075/M8215 12V Pump & Motor $616.93
Seawater RO Membrane 2.5″ x 14″ $240.00
Membrane Housing 2.5″ x 14″ Fiberglass ????
2X Prefilter housings $28.57/each
6-pack 5 micron Prefilter $23.49
6-pack 20 micron Prefilter $19.99
Brine water outlet $7.49
Primer pump $25.00
Waterhose $27.99
3-way valve $20.99
Steelfittings $15.99
3-way T-fitting $13.99
Endplugs $8.99
Preasure Gauge $11.95
Needle Valve $75.00

Total cost for all parts: $1 139.94


I’ve used several blogposts and Youtube videos as a reference for this project and I would like to give credit to all the sources I used for knowledge and inspiration.
I would recommend that you check them all out before you start your own DIY Watermaker project.

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