Why Humans Can’t Drink the Sea
Although oceans cover 70% of the Earth, their water is undrinkable for humans.The reason is simple—but deadly: salt.
Human blood and cells contain about 0.9% salt (the same as medical saline). Seawater, however, contains about 3.5% salt—nearly four times higher. When we drink seawater, instead of hydrating us, it actually draws water out of our cells.
Our kidneys are not designed to remove salt as efficiently as fish gills. To flush out excess sodium, they must use more water than we gain from seawater, which quickly leads to severe dehydration and potential organ stress if untreated.
· In short: humans are biologically built for freshwater, not seawater.
Born to the Ocean: How Marine Creatures Outsmart Salt
Marine organisms live in the same salty oceans, yet they flourish thanks to osmoregulation—the process of balancing water and salt inside their bodies.
- Bony fish pump out excess salt through their gills and produce highly concentrated urine to conserve water.
- Sharks and rays balance their internal fluids by storing urea, making their bodies almost as salty as seawater.
- Invertebrates like jellyfish or crabs simply let their body fluids match the ocean’s salinity, adapting to it naturally.
· Nature is truly remarkable. Evolution has equipped marine organisms with unique “salt-handling” abilities, perfectly tailored for ocean life. Humans, however, are land-dwellers—our biology never needed to evolve the same tools to adapt to the salty water environment.
Reverse Osmosis: Humanity’s “Artificial Gills”
At this point, you might wonder: If humans can’t drink seawater, are we forever unable to use the largest reservoir of water on Earth?
The answer is inspiring. What natural evolution didn’t provide, human ingenuity created: seawater desalination.
Today, the most effective method is Reverse Osmosis (RO):
Seawater is pushed through a semi-permeable membrane. Water molecules pass through, while salts and impurities are blocked. The result is fresh, safe drinking water—up to 99.9% desalinated.
· In a way, RO is our man-made version of fish gills—except on an industrial scale, making the ocean’s water truly accessible to humanity.
HJC RO Membranes: Advanced Global Solutions
With population growth and climate change driving freshwater scarcity, seawater desalination is no longer optional—it is essential.
At HJC, our commitment goes beyond providing products.
As innovators in high-salinity water treatment, we aim to serve industries and communities while contributing to a cleaner, more sustainable planet.
As a leading provider of advanced RO membrane technology, we understand the critical role water plays in sustaining both life and the environment. We focus on advanced reverse osmosis membranes designed for seawater desalination, brackish water treatment, and high-salinity applications.
Our Advantages:
- High Salt Rejection: Up to 99.8%, even in extreme seawater conditions (TDS > 35,000 ppm).
- Energy Efficiency: Optimized design for lower operating pressure and reduced energy costs.
- Durability & Reliability: Long service life with stable operation across municipal, industrial, and household systems.
- Trusted Worldwide: Applied in 70+ countries, powering desalination plants, island water supply, ships, and industrial reuse.
· While nature gave fish the ability to survive in saltwater, HJC provides humanity with the technology to transform oceans into life-sustaining freshwater.
Discover HJC RO membrane solutions→ Contact us