Modular Desalination Pods Tap the Ocean’s Depths

One of the recurring themes on our site is desalination. We have covered a wide range of technologies designed to extract drinking water from seawater—from portable, solar-powered kits to large-scale desalination plants using cutting-edge reverse osmosis systems to serve millions in arid regions. This time, we spotlight an unconventional solution: a set of low-profile pods anchored to the ocean floor. Developed by a U.S.-based company, this experimental technology offers an offshore alternative to traditional land-based plants. The team behind it calls the system a “water farm,” and one of its standout features is its modular design. 

What are desalination pods?

This is a novel deep-sea desalination approach that deploys a series of pods on the ocean floor, roughly 400 metres below the surface. These pod-like units—designed with a blister shape and tethered to the seabed via cable—feature a freshwater pipe that runs to the surface. They tap into the immense hydrostatic pressure at that depth to drive the reverse osmosis process, filtering out salt, bacteria, viruses, pesticides and PFAs. In short: they produce potable water. Each pod, according to its developers, can generate around 4,000 cubic metres of fresh water per day.

The system, known as Deep Sea Reverse Osmosis (DSRO), is designed to scale easily thanks to its modular configuration, allowing installations to be tailored to local demand. The pods are engineered to withstand the harsh pressures and corrosive environment of the deep sea. Initial trials have been conducted at the U.S. Navy’s Deep Ocean Simulation Center. The next milestone is an open-water pilot off the California coast—a state grappling with worsening droughts and wildfire seasons. For now, beyond the engineering challenge of operating at depth, one of the main hurdles is bringing down the steep deployment costs.

How does a DSRO desalination plant work?

Conventional reverse osmosis relies on high pressure to push seawater through membranes that filter out salts and impurities. DSRO flips the script by taking advantage of the ocean’s natural pressure at depths of 400 to 600 metres to drive the filtration process, dramatically cutting energy use in the process.

Although the concept dates back decades—almost to the early days of reverse osmosis—it is only recently that it has become viable, thanks to advances in subsea robotics and underwater sensing technologies.

Producing desalinated water with renewables

Beyond efficiency gains, another major focus in the next generation of desalination is integrating renewable energy. A study from the Institute for Water and Environmental Engineering (IIAMA) at the Polytechnic University of Valencia found that solar-powered systems can cut desalination costs by up to 24%.

One standout example is the Al Khafji plant in northeastern Saudi Arabia, widely seen as a trailblazer in sustainable desalination. Powered entirely by solar photovoltaics, the facility sharply reduces fossil fuel use—lowering both its carbon footprint and its operational expenses.

With a daily output of 60,000 cubic metres, it supplies water to over 150,000 people in a region facing acute water scarcity. Its success has inspired similar projects across the Gulf, positioning it as a benchmark in the shift toward cleaner, more energy-efficient desalination solutions.

Source:

• TechCrunch