You could be doing more harm than good by choosing “pure and natural” bottled water over tap water, as new figures reveal some bottled water contain dangerous levels of acid.

Water straight from the tap ranked among the best quality for drinking in Australia when compared to market leading water brands like Pump and Mount Franklin.

In the season two premiere of ABC’s War on Waste popular water brands were put to the test, comparing them to Gold Coast water in a Griffith University’s testing labs.

Australian tap water is well-regulated to ensure it’s safe to drink but bottled water is classified as a food product and not subject to the same controls, which means quality can vary depending on the brand.

Tests show that when it came to mineral content, calcium and magnesium, tap water had the highest concentration out of all brands, except Fiji.

The first test revealed Gold Coast tap water had higher levels of minerals than several of the brands. Picture: ABC

Water scientist Dr Fred Leusch also looked at the pH levels or acidity, with a seven being neutral and any number below considered too acidic and potentially harmful for teeth enamel.

Tests found three popular bottled waters – Mount Franklin, Mount Franklin lightly sparkling and Pump – contained below safe levels of PH, respectively 4.8, 3.7 and 4.6.

The red coloured figures show the brands that had higher acidity because they were below the neutral level. Picture: ABC

“Below four is something that does damage your enamel,” Dr Leusch said.

“We’re in the range of Coke and coffee — we know these are not great for our teeth. 

“Tap water should really be marketed as mineral water.”

War on Waste also highlighted how Sydney-based Nature’s Best is essentially charging customers for packaging, as the water, although treated, comes straight from the tap.

Labelled as “pure, safe, Australian water”, Dr Leusch said: “I find the name ironic — Nature’s Best, pure, safe Australian — it’s an acknowledgment that tap water’s safe,” he said.

“In the end, I reckon when you’re buying this, most of the cost is the plastic container. What’s inside is just worth 0.1 of a cent.”

For people who avoid fluoride in their water, it’s in the bottled stuff too, with the tests finding all bottled water containing some fluoride.

Even bottled water had fluoride in it, with the Nature’s Best brand having slightly more than the tap water. Picture: ABC

“It’s a chemical found in rocks and so if that groundwater has been in contact with fluoride containing rocks, it will have naturally higher concentrations of fluoride.”

Dr Leusch said it was easy for people to get confused and fall for market “gimmicks” used to persuade them into buying things they don't truly need.     

“All our water is eventually from the same place, it’s a closed cycle,” he said.

“The water that fills our rivers is actually sometimes fed from the ground, sometimes fed from rainwater — it’s all the same water in the end.

“Because they’re regulated as food the words can have a very specific meaning — spring water must really mean it’s sourced from groundwater. Pure water is more generic than that and it can actually be tap water that has been filtered and bottled into this.”

Article created in partnership with Over60