Learn
How reverse osmosis works.
Reverse osmosis uses pressure to push water through a semipermeable membrane. The purified water (permeate) is kept and the concentrate is discharged. Here is what happens in each stage, what it does and does not do, and how to keep a system working well.
The three stages
- Stage 1
Pre-filtration
Sediment and carbon filters catch particles and chlorine before the water reaches the membrane, protecting it.
- Stage 2
The membrane
Pressure pushes water through a semipermeable membrane. Purified water passes through, while most of the dissolved salts are flushed away.
- Stage 3
Polish & store
A final filter polishes the taste, and a small tank keeps purified water ready at your tap.
Most systems add a pump and a pressure gauge; larger units add pretreatment and a control panel. The exact configuration of each model is on its spec sheet.
What RO reduces, and what it does not reliably remove
The membrane rejects most dissolved salts and many dissolved contaminants, which is why RO water tastes clean and why a TDS meter reads much lower after the system than before. The carbon stages reduce chlorine, taste and odour. Together, that covers the things most people notice in municipal water.
RO is not a guaranteed barrier for every substance. Some dissolved gases pass through, performance against specific contaminants varies with the membrane and the feed water, and no filter makes water sterile on its own. We do not make health claims for any system. If you have a specific concern, test for it first and treat for it specifically.
Why feed water, pressure and temperature matter
A membrane works by pressure difference. Low supply pressure means less permeate and more concentrate, which is why small systems include a pump and why we ask about your supply. Cold water is more viscous and passes the membrane more slowly, so winter output is lower than summer output for the same system.
The feed water sets the workload. High salt content, hardness, iron or manganese load the membrane faster and can foul or scale it. That is where pretreatment comes in, and why the GPD rating on a box is a test-condition number rather than a promise for your tap.
Maintenance basics
Pre-filters protect the membrane and are replaced periodically; the membrane itself lasts longer and is replaced when output drops or the after-RO TDS rises. Intervals depend on your water quality and how much you use, so follow the manufacturer’s schedule in your system’s documentation rather than a generic rule.
Two habits keep a system healthy: change filters on schedule even if the water still tastes fine, and check the after-RO TDS reading now and then. A rising reading is the earliest sign the membrane needs attention.
Borehole and problem water
Borehole water varies from excellent to unusable, sometimes within the same farm. Have it tested before you buy. Hardness, iron, manganese, high salt and sediment usually call for pretreatment ahead of the membrane: a sediment stage sized for the load, softening or iron removal where needed, and sometimes a larger system running below its rating so the membrane lasts.
Send us a lab report with your quote request and we will tell you plainly whether a system suits your water and what it needs in front of it.
Check your own water
Got a TDS meter? Put your reading on the scale to see which band it falls in. Or answer seven quick questions and we will suggest a system size, confirmed within 24 hours.