Bottled Water versus Tap Water

Blue montage of plastic bottles

I wrote this article after I was (rightly) challenged on some of the sources of my arguments about bottled water. I’m often heard saying that one of the easiest ways to reduce your carbon footprint is to give up bottled water and that tap water is just as good – if not better – but it turns out that this isn’t always true.

I do my absolute best not to fall into the trap of repeating environmental mistruths but sometimes I fail. One of the things I love about writing this website is how it forces me to test the validity of rumours, even those I’d dearly love to be true. Most people hate being wrong. I don’t mind really. In fact I see it as a good thing. It means I’ve just learned something new. Here’s what I’ve learned about bottled water versus tap water.

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Chemicals in Bottled Water
You may not be aware but plastic bottles are slightly permeable allowing chemicals to be absorbed into them over time. For this reasons it is recommended that bottled water is stored away from noxious chemicals or strong odours. I’ve had a read of the Irish legislation around bottled water and couldn’t find any stipulations on how bottled water should be stored, which is a bit concerning.

The International Bottled Water Association says that there is no requirement for best before dates on water for safety reasons and that it’s really more to do with stock rotation. This doesn’t make sense to me. If the bottles that contain the water are slightly permeable isn’t there a risk of the water spoiling over time. I’m not a chemist so may be completely off the mark on that one, but I do know that research in Canada, the US, Iran and the United Arab Emirates have all shown that antimony (a mineral used in plastic manufacturing) can leach from PET bottles into water contained therein.

It’s worth noting that antimony is naturally occurring mineral and exists in most foods, typically at a rate of the 0.2 to 1.1 parts per billion (ppb). Antimony is not classed as a carcinogen and it’s harmful effects are generally related to breathing it in, not ingesting it. Also and the level of antimony found in bottled water research referred to above didn’t exceed the level recommended by the world health organisation of 20 parts per billion (20ppb/20 µg/litre).

However if the bottled water is subjected to high heat for extended periods the contamination levels could pass limits set by The German Federal Ministry (5ppb), Japan (2ppb), Health Canada and the US (6ppb). In the research carried out in the US the maximum contamination level of 6ppb was passed after 176 days when bottled water was store for 60°C, in 38 days at 65°C, in 12 days at 70°C, in 4.7 days at 75°C, in 2.3 days at 80°C and in 1.3 days 85°C.

In Ireland bottled water is unlikely to be exposed to high temperatures or stored for long periods, especially if it’s bottled locally but it’s worth being aware of the issue of antimony all the same, particularly if the main reason you’re drinking bottled water is for health reasons.

Plastic Particles in Bottled Water
In 2018 in an analysis of 259 bottles from 19 locations in nine countries across 11 different brands, 325 plastic particles was found for every litre of water being sold. In one bottle of Nestlé Pure Life, concentrations were as high as 10,000 plastic pieces per litre of water. Of the 259 bottles tested, only 17 were free of plastics and according to the scientists they “found roughly twice as many plastic particles within bottled water” compared with their previous study of tap water (Source: The Guardian). Again whether plastic in your drinking water is a health risk has yet to be proven but it’s not something I’d personally be keen to do on a regular basis.

Other Health Impacts of Bottled Water
Some health risks related to drinking bottle water have nothing to do with plastic. For example drinking low mineral water has been shown to cause low bone density in female rats (poor rats).

I had read that sparkling water can be bad for your teeth but having drilled down on the research it seems that myth has been debunked. Recent research now suggests that erosion caused by carbonated water is not enough to be of concern, particularly if you use a straw (reusable please) to drink it!

The Carbon Footprint of Bottled Water
The Bottled Water Association states that it takes 1.39 litres of water to make a 1 litre bottle of water, but Nestle’s website says their water takes 2.5 litres of water to produce one litre! But who cares? Sure isn’t there tonnes of water falling from the sky in Ireland almost everyday. Well yes and no.

We’ve plenty of rain but we don’t drink rain water or use to make food / drinks (and plastic) before putting it through a lengthy cleaning process that involves lots of energy and chemicals.  This lengthy, energy and chemical intensive process is the reason we need to be mindful of our use of water. Every time we use a litre of water for unnecessary reasons we’re using up energy and resources that could have been employed elsewhere. Knowing that is using 39% more water for bottled water justified?

Also a research study in Spain in 2021 found that, in comparison to tap water in Barcelona, bottled water is 3500 more damaging to the climate and 1,400 more impactful on ecosystems

On average a 500-milliliter bottle of water has a total carbon footprint of about 3 ounces of carbon dioxide. You can read more about the carbon footprint of bottled water in this article and in this very comprehensive literature review of paper on the carbon footprint of bottled water carried out by a water filter manufacturer in America.

When I doing some research for this article I discovered that some of the bottled water in Lidl was sourced in the UK, which means we’re shipping water over water using fossil fuels to a country with plenty of it on tap. Crazy, eh?

The Ethics of Bottled Water
This has happened in Ireland as of yet but companies are being the right to bottle water even when the areas face drought including South Eastern Australia, and California.

There are also concerns that harvesting water on a commercial level negatively impact on the affected eco-system.

Nestle are one of the largest sellers of bottled water and have been criticised for taking more water than they weren’t entitled leading to degradation of the natural environment. It’s also claimed that they pay pennies for the rights to this precious resource. You can read more about the campaign to curb Nestle’s water harvesting exploits on the Story of Stuff Website

Different Quality Requirements
I have read that bottled water isn’t required to meet the same standards as tap water. It is true that the regulations for bottled water and drinking water differ in Ireland but according to my un-trained eye there doesn’t appear to be a lower standard for bottled water, in Ireland anyway.

In the supermarket / store you will come across different types of water. Spring and mineral waters both have to come from protected underground sources, with mineral water needing also to contain a minimum amount of trace elements to brand itself as mineral. Bottled water that isn’t labelled as spring or mineral does not have to be from an underground source and could just be bottled tap water!

The Cost
Currently we pay for the water that comes out of our tap through general taxation so it’s really hard to put a price on it, but taking the charge that will be levied on households that exceed their 213,000 litre allowance in 2021 of €1.85 per 1000 litres we pay approximately .00185c per litre. That’s not even one cent per litre.

The cheapest bottled water I found in my local Lidl was 45 cent per two litres, which equates to 22.5 cent per litre. This means that the Lidl water is approximately 122 times more expensive than tap water. If you equate that to cost of a pint of beer in the pub, it’s like paying €730 for your pint. Worse still if you buy a 500ml bottle in a shop at €1.00 – €1.50 , which equates to €9,730 in pint language (€6 x 1622)

Issues with Tap Water
Before I finish It would be remiss of me not to acknowledge the health concerns that some people have around our tap water.

I appreciate that some people have no choice but to drink bottled water due to the failure of the state to provide them with a reliable supply of clean drinking water. The fact that this problem continues to exist in Ireland in 2021 is shocking, but is beyond the scope of this article and website.

I have long been aware of a large minority of the population that are against fluoride in our water supply due to concerns about it’s harm to our health. Fluoride is added to the water supply in Ireland in order to reduce dental cavities, but an article in the Harvard Public Health Magazine in 2016 indicates that countries that have employed different dental protective measures have seen similar reduction rates to countries that fluoridate their water. Also research published in the Scientific World Journal in 2014 suggest that the World Health Organisation needs to review it’s endorsement of water fluoridation in recognition of ‘the established and potential harms currently attributed to fluoride’. More worrying is a 2014 article by Dr Philip Michael, Honorary Secretary of the Irish Doctors Environmental Association, which talks about the higher cancer rates in Ireland compared to Northern Ireland and Europe (excluding Spain), where water is not fluoridated.  That said research from 2014 didn’t find any link between an increase in bone cancer and fluoride in water and neither did a review on the effect of water fluoridation on health by the HSE.

Intriguingly it seems that research into the whole area of fluoride’s impact on health is fraught with hostility, making it impossible to have a reasonable discussion on this issue. What’s a concerned person to do? Well you’ve a few options;

  • Take a view that fluoridation is not something you’re going to worry about and do nothing
  • Buy bottled spring or natural mineral water.
  • Install a water filter that removed fluoride

I’ve had a quick look into water filters that remove fluoride and there appears to be quite a bit of confusion over whether the filters only remove naturally occurring fluoride or the type that’s added to our municipal water supply. I contacted four and each told me that they can provide filters that remove fluoride that’s been added. Here they are, in no particular order of preference

Also here’s a very thorough analysis of the sustainability of various types of water filters, albeit from an American perspective.

One of the other concerns with our tap water relates to lead leaching in from pipes. This appears to be predominately an urban issue and is down to the type of pipes used to connect homes to the main water supply. If you’re worried you can undertake a simple and inexpensive test to confirm the existence or absence of lead in your water pipes. Unfortunately if you do find it in your pipes there is some financial assistance to replace them. If you earn under €75,000 there are two types of grants, but even if you earn over this amount you may still be get a tax credit for the work under the HRI scheme. More information on financial assistance available here.

On a positive note scientists in Trinity College discovered that tap water can actually protect you from microplastics in boiled water!

If you’re part of a school you might be interested in Newpark School in Blackrock who successfully managed to ban single-use plastic from their school. Here’s a link to their plastic-free policy. They estimate that they save a whopping 16,000 plastic bottles every year.

In Tipperary 50 primary schools trialled giving up plastic in their lunchboxes as part of a campaign by Plastic Free Schools

In Conclusion
Sorry, if I’ve made your head ache a bit. I started out this article hoping to provide clarity and certainty, but life doesn’t go that way sometimes, and neither does this website!


Published by Elaine Butler

I am a circular design consultant helping manfacturers prepare for the circular economy

5 thoughts on “Bottled Water versus Tap Water

  1. Very interesting…
    I will probably go for option one..
    I have the sightly cynical reasoning that if the government realised that adding flouride was costing them money (by increasing health problems like cancer) they would be interested and stop it.
    In the mean time, it helps out kids in households where toothbrushing isn’t regular.


    1. I was of the same mind in the past but I do remember reading how it took hospitals 20 years to stop giving pregnant women xrays after it was linked with childhood leukaemia. People can be slow to change and sometimes people day while we’re waiting.


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