Most comparisons weigh the equipment. This one weighs the water: what it is actually like once it comes out of the tap, and where that suits a use and where it does not. Some of the answers are counterintuitive, particularly for households who assume the most thoroughly treated water is automatically the best water for everything.
Drinking and hot drinks
The pro is that it tastes of nothing in particular, which is what most people want from drinking water, and it carries none of the chlorine or earthy notes that prompt complaints. The con is that fresh permeate tastes flat, because the minerals that give water character have been removed with everything else, and it is noticeable in tea and coffee where mineral content affects extraction. A remineralization cartridge resolves both, which is why it is worth fitting from the start rather than as an afterthought.
Cooking and ice
Cooking is a clear pro. Water reduces as it simmers, concentrating whatever it carries into the food, so treated water is a genuine improvement in stocks, sauces and anything cooked for a long time. Ice is another: dissolved minerals and air are what make ice cloudy and give it a taste, so ice from treated water is clear and neutral. The only con here is capacity, since an ice maker draws far more than a drinking tap and can outpace a small storage tank.
Plants, aquariums and appliances
For most houseplants, reverse osmosis water is fine and unnecessary. For aquariums it is a genuine pro, because it gives a blank base to build known water chemistry on, which is why it is standard in reef keeping, and it must be remineralized deliberately for the species involved rather than used bare. For steam irons and humidifiers it is excellent, since there is almost nothing left to deposit. For a car rinse it is not the tool, because deionizing resin is what removes the last dissolved content.
The honest limits
It is one tap, so the shower, the washing machine and the water heater are untouched and any hardness complaint remains. Demineralized water is mildly aggressive to metals, which is why whole house systems remineralize before the water enters pipework. And it takes a reject stream to produce, which is the mechanism rather than waste. Where those trade offs suit the household, the water is excellent. Our reverse osmosis guide covers the systems that produce it.
Questions people ask about pros and cons of reverse osmosis water
Does reverse osmosis water taste better?
It tastes of nothing in particular, which is usually the goal, though fresh permeate is flat until a remineralization stage is fitted.
Is it good for cooking?
Yes. Water concentrates as it reduces, so anything simmered for a long time carries whatever the water contained.
Should I use it for an aquarium?
It is standard for building known water chemistry from a blank base, but it must be remineralized deliberately for the species kept.
What is the main limitation?
It treats one tap, so showers, laundry and the water heater are unchanged and any hardness complaint remains.