What reverse osmosis water actually is

Reverse osmosis, or RO, is a filtration method that pushes water under pressure through a very fine semi-permeable membrane. The pores in that membrane are tiny, down around 0.0001 of a micron, which is hundreds of thousands of times smaller than a human hair. Anything bigger than a water molecule struggles to get through.

That is what makes RO so thorough. As water passes through, the membrane reduces a long list of dissolved contaminants, including fluoride, chlorine, nitrates, heavy metals like lead, pesticides, PFAS and microplastics, along with most of the dissolved minerals in the water. A good RO system removes up to around 95 to 99 percent of total dissolved solids. The result is exceptionally clean water, which is exactly why RO is used everywhere from bottled water production to laboratories and medical settings.

It is genuinely the most complete filtration you can put under a kitchen sink. But "removes almost everything" is also where the worry starts, so let us deal with it head on.

So is RO water safe to drink?

Yes. RO water is safe to drink, and it has been consumed safely by millions of people for decades. There is nothing dangerous about water that has had its dissolved contaminants removed. If anything, RO water is cleaner than almost any other water you could drink.

When people ask whether RO water is "safe," what they are usually really asking is one of two things: does removing the minerals make it bad for me, and is very pure water somehow harmful over the long term. Those are fair questions, and they deserve a proper answer rather than a marketing brush-off.

The big one: does RO remove healthy minerals?

Yes, it does. This is not a myth. Along with the contaminants, basic reverse osmosis also removes beneficial minerals like calcium and magnesium. There is no point pretending otherwise.

The important part is the context that usually gets left out. The minerals in your drinking water make up only a small fraction of your total daily mineral intake. The overwhelming majority of the calcium and magnesium your body uses comes from food, things like dairy, leafy greens, nuts, legumes and wholegrains, not from your tap. So for someone eating a reasonably balanced diet, the minerals lost through drinking RO water are a minor contribution that is easily covered by what is on your plate.

It is true that the World Health Organisation has published discussion on the long-term consumption of demineralised water, and it is worth being honest that this is a debated area rather than a settled one. The concerns raised there are most relevant in situations where water is a major source of dietary minerals, or for very low-mineral water consumed as the sole supply over long periods. For most Australian households with a normal, varied diet, mainstream guidance does not treat drinking RO water as a health risk.

In other words, the minerals question is real, but for most people it is a small one. And as you will see in a moment, there is a simple way to remove it from the equation entirely.

Does demineralised water "leach" minerals out of your body?

This is the claim that does the rounds online, that pure water acts like a magnet and pulls minerals out of you. It is overstated. Water with very low mineral content can dissolve minerals it comes into contact with, which is part of the WHO discussion above, but the idea that drinking it strips significant minerals from a healthy body on a normal diet is not well supported. Your body is not a sealed beaker, and your diet is doing the heavy lifting on minerals regardless of what you drink.

If you have a specific medical condition or you have been told to manage your mineral intake carefully, that is a conversation for your GP, not a water filter company. For everyone else, this particular fear is far bigger online than it is in reality.

How remineralisation settles the whole debate

Here is the part that makes most of the minerals argument moot, at least with the right system. A basic RO unit just strips and stops. A better one adds the good minerals back.

Our PureFlowreverse osmosis system runs the purified water through a remineralisation stage that reintroduces minerals like calcium and magnesium after filtration. That does two things. It puts back the beneficial minerals that people worry about losing, and it balances the water so it tastes smooth and clean rather than flat. The water comes out at a mildly alkaline pH of around 9, which is simply a reflection of those minerals being added back rather than any claim of special powers.

We want to be straight about that last point, because the internet is full of big promises about "alkaline water." The honest version is more modest. Remineralisation restores the minerals RO removes and improves the taste. That is the genuine benefit, and it is the one that matters. It means you get the thorough contaminant removal of RO without the demineralised-water concern, because the minerals are not staying gone.

So if the "RO strips your minerals" worry is what is holding you back, a remineralising system answers it directly.

Is RO water acidic, and what does it taste like?

Pure RO water, straight off the membrane with nothing added, can sit slightly on the acidic side of neutral and can taste a little flat to some people, because the dissolved minerals that give water its "mouthfeel" have been removed. Neither of those is harmful in the amounts you would drink, but they are real, and they are another reason the remineralisation stage matters. Adding minerals back lifts the pH to that mildly alkaline level and rounds out the taste.

Most people who switch to remineralised RO notice their water tastes cleaner and crisper, and that tea and coffee taste better too, because the chlorine and off-flavours are gone. Taste is subjective, but it is consistently one of the first things customers mention.

Does RO water even make sense in Melbourne?

This is where we will be honest in a way a lot of filter companies will not be. Melbourne's tap water is genuinely excellent. It comes from protected mountain catchments, it is very low in dissolved solids, typically somewhere around 11 to 38 mg/L, and it is consistently rated among the best mains water in the country. You do not need reverse osmosis to make Melbourne water safe, because it already is.

So RO here is not about fixing a crisis. It is about going further. It makes the most sense if you fall into one of these groups:

• You want to reduce fluoride in your drinking water, for personal preference or for preparing infant formula. RO is one of the few methods that meaningfully removes fluoride, since standard carbon filters do not. Worth noting that fluoride is added to support dental health, so reducing it is a personal choice rather than a safety fix.
• You want the absolute cleanest possible glass for drinking and cooking, with chlorine, taste and odour removed and contaminants like lead, nitrates and PFAS reduced to the lowest practical level.
• You simply want peace of mind and water that tastes its best, and you are happy to invest in that.

If what you mainly want is chlorine taken out of your showers so your skin and hair feel better, that is a whole house filter job, not an RO one. RO is point-of-use, usually at the kitchen sink, for the water you drink and cook with. The two solve different problems, and plenty of homes use both.

A few quick myths, cleared up

"RO wastes huge amounts of water." A small amount of water is used to flush the membrane and keep it working properly, but on a system that is sized correctly for your home, that is negligible next to the drinking and cooking water a household uses. Sizing it right to your setup is part of a proper install.

"RO removes everything, so it removes the good stuff too." It removes the minerals, yes, but as covered above, those come mostly from food, and a remineralising system puts them back anyway.

"RO water is bad for you long term." For a healthy person on a normal diet drinking remineralised RO water, there is no good evidence of harm. The long-term concerns that get quoted relate to very low-mineral water as a sole source, which is not the situation for a typical Melbourne home.

Our honest take

Reverse osmosis water is safe to drink. The "it strips your minerals" worry is the one real point in the whole debate, and even that is minor for most people on a normal diet, and it disappears entirely with a system that remineralises the water afterward. What you are left with is some of the cleanest, best-tasting water you can get at home.

The honest catch for Melbourne is that you do not need RO to be safe, because your tap water already is. RO is the choice you make when you want to go further, whether that is reducing fluoride, getting the cleanest possible drinking water, or simply enjoying how it tastes.

If you are weighing it up, the best place to start is knowing what is actually in your water. We are a Melbourne team, and we will come to your home, test your tap water for free, explain the results in plain English, and tell you honestly whether RO is worth it for you.

Book your free water test and get a straight answer before you decide.