Spoiler alert: Yes, RO does remove nitrates. Very effectively, in fact. We’re talking about a 90% to 97% removal rate, which is pretty darn impressive for a machine that mostly just pushes water through a fancy filter. But—and this is the ironic part—it only works if you have the right setup.
You see, nitrates are tiny molecules. They’re not like the big, chunky sediment that gets caught by a coffee filter. They slip right through standard carbon filters. That’s why RO uses a semi-permeable membrane, a microscopic sieve that forces even those sneaky nitrate ions to tap out and go down the drain. (Spoiler: they literally go down the drain as brine).
But Wait—Hold Your Tap Water
Here’s where Dave almost threw his RO unit out the window. If you buy a cheap “RO system” from a shady website, it might only come with a sediment filter and a carbon block. That will not touch nitrates. You need the actual RO membrane—the heart of the system—to be present and accounted for. Check the box, people. Don’t be a Dave.
Also, water pressure matters. If your water pressure is low (below 40 psi), the RO membrane gets lazy. It might only remove 70% of nitrates instead of 95%. That’s like having a bouncer who only checks IDs every third person. Not ideal. A booster pump can fix that, but it’s an extra cost.
Does Reverse Osmosis Remove Nitrates From Water?
