Before buying a whole house water filter, it might understand osmosis, particularly the differences between forward and reverse osmosis. Also, how they could benefit your health and that of your family. According to the Centers for Disease Control and Prevention, filtering your water is crucial. This is to improve its taste, but to remove chemicals, and other dangers.


The water that you drink, whether it comes from a tap or a bottle, requires filtering. Municipal water tests positive for so many contaminants it is not safe for human consumption. From heavy metals to pharmaceutical drugs and even sewage, infrastructure for treating water is not performing as it should. There is even microscopic plastic in your water, certainly hordes of microbes too.

You need to purify. Sure, contaminants in municipal water often test within “safe” ranges for folks to drink. It often tests insanely high too, where there should be no dangers lurking in your drinking water anyway. You must filter your water, and you can in several ways. From investing in a whole house water filter to using osmosis and reverse osmosis systems, just make sure that you do.


Osmosis refers to forward osmosis, a process where pure water flows through a semi-permeable membrane from a dilute solution to a solution with a much higher concentration. A semi-permeable membrane will allow small ions and molecules through it, but it will prevent entry for any dissolved substances and all larger molecules, effectively filtering water of most impurities.

As an illustrating example, think of a tank with two compartments, separated by only a semi-permeable membrane that allows water through, but not salt. If one compartment contains pure water and the other a salt solution, then the system will attempt equilibrium by trying to achieve the same concentration each side. However, it can only do this by moving pure water into the saltwater tank.

As water moves through the membrane into the salty compartment, liquid levels will rise in the saltwater tank and sink in the pure one. This will continue until it generates sufficient pressure, caused by level differences between the two compartments, to stop the process of osmosis. This pressure, called osmotic pressure, equals the force exerted in trying to equalize concentrations in both tanks.


You can reverse this movement. By applying higher pressure to the higher concentration compartment than the osmotic pressure, you can create a process of reverse osmosis. Using the same example above for illumination purposes, reversing the flow will remove salt from the water. Also, send it to the pure water compartment, since the membrane is impermeable to salt.

The movement of molecules from a higher concentration to a lower concentration is diffusion. Osmosis is a specific type of diffusion where the molecules are water, and a semi-permeable membrane filters it through the concentration gradient. This membrane, being semi-permeable, allows water to move through, but not large molecules, such as bacteria, sewage, and glucose.

Both osmosis and diffusion continue unabated until the point of equilibrium. You can slow, stop, even reverse osmosis by simply applying enough pressure from the side with the highest concentration. Reverse osmosis moves water against the concentration gradient, from high to low, effectively purifying water and making it suitable for consumption.


Forward osmosis moves water with the concentration gradient, so from low to high. Reverse osmosis moves it back the opposite way. Osmotic pressure occurs on the side with the highest concentration in forward osmosis. It is the other way around, occurring from the side with freshwater in reverse osmosis. Osmosis adds nutrients, chemicals, or other concentrations to water, while reverse osmosis purifies water and removes these substances from it.


When looking at buying a whole house water filter for your home, consider one that utilizes reverse osmosis. Not all systems require this, but it adds a twofold authentication that guarantees water purity. Reverse osmosis is the crème de la crème of water filtration systems, and despite it being pricier than other systems, you can still find plenty of affordable options for home use.