Water. Its essential to life, in fact most people will die within three or four days without water. But what if the water you do drink is making you sick? We've all heard the stories that tap water is perfectly safe, and just as good to drink as bottled water, but what's the real story? Read on to find out.Why Water Quality MattersFrom altering the composition of cells, regulating body temperature, providing the medium for chemical and metabolic reactions, to transporting nutrients and removal of waste products, water is an essential part of the physiological functioning of the body. We've all been told that the body is 60 - 65% percent water, shouldn't it make sense that the quality of water that we drink is important? Still its a question that many people don't think to ask.What's Wrong With Tap Water?Tap water can contain a variety of different contaminants. Next we will cover some of those we should be concerned with most.Chlorine: Chlorine is added to the water supply as a way to guard against bacteria in the water supply. It is a strong disinfectant. In NZ, treatment plant operators use a rating called free available chlorine (FAC) to check the levels of chlorine in the water supply. Basically they are checking that chlorine levels do not fall below a certain level. The problem with this is the number of potential health issues that go along with the ingestion of chlorine and chlorine byproducts. For instance, consumption of chlorine byproducts in drinking water is shown to be linked to bladder and rectal cancers in humans (1). Chlorinated water exposure is also linked with increased risk for developing childhood asthma (2). Ass cancer and asthma you say? Sounds like a party...Fluoride: Fluoride is added to the water supply in most areas in New Zealand, ostensibly to help with dental cavities. Unfortunately, fluoride exposure may also cause a plethora of negative health outcomes. It has been shown to be a neurotoxin in animals and humans. Children in high fluoride areas have also been found to have significantly lower I.Q scores than children in low/no fluoride areas (3).One of the forms of fluoride added to the New Zealand water supply is sodium silicofluoride. What is frightening about this is the fact that a patent exists for using this exact substance to remove lead from brass! So... there is a substance being added to our water supply that leaches lead into the water from all the brass tap and water fittings it comes into contact with? How's that nice cool glass of tap water looking now?If that wasn't bad enough, one of the other main forms of fluoride added in New Zealand's water supply is hydrofluorosilicic acid. You would think this would be some kind of pharmaceutical grade additive surely? Sorry- its an industrial waste product of aluminum production. Gross. If I put my tinfoil hat on for a minute (pardon the pun) you'd have to wonder how and why an industrial waste product that was otherwise becoming expensive to dispose of, was all of a sudden around 1945 deemed a safe and necessary additive to the water supply (creating another multi-billion dollar industry in the process). Sodium fluoride is even the active ingredient in many insecticides, fungicides and wood preservatives. Even if it does help prevent cavities (which is actually still up for debate), the harm greatly outweighs the benefits of having this highly toxic substance added to our drinking water.Other Contaminants: As if all this wasn't bad enough a multitude of other contaminants have been found in tap water, including but not limited to lead, cadmium, arsenic (also found in low levels in the fluoride itself), pesticide residues, prescription and recreational drug residues, hormones, mercury, copper, nitrates etc etc etc. Even flame retardants, plasticizers, cosmetic compounds, and solvents have been found in treated tap water!!! (4). To put it mildly, tap water should definitely not be your go to source for drinking.So I Should Choose Bottled Water, Right?Not so fast. Humans are currently producing plastic bottles at the rate of 20,000 bottles per second! In fact, 480 billion plastic bottles of water were sold in the year 2016 alone (5). As the production of plastic bottles continues to skyrocket, the systems in place to reclaim and recycle this enormous amount of new garbage have been simply unable to keep up. Sadly much of this waste ends up in our oceans.Ecological disaster aside, that's still not the only problem with bottled water. There is also the question of bisphenol A (BPA) contained in plastic bottles. BPA has been shown to produce abnormal reproductive systems in animal models and is known to leach in small amounts into water and food stored in such containers (6). This has led to some countries phasing out its use in food packaging. Unfortunately even BPA free bottles may be no better as these often contain fluorene-9-bisphenol, or BHPF. Researchers at Peking University have found that during tests on mice, that those animals exposed to BHPF have smaller wombs and pups and suffer a higher rate of miscarriges (6). Sounds like great stuff to have leaching into your 'healthy' bottled water no?So What to Do?If it seems like all this is a lot to take in, there are some relatively simple steps you can take to improve the quality of water that you consume. The easiest way to ensure the water you drink is clean is to use a home filtration system. Which system you choose will depend on your budget and where you live, but there are a number of good options that are relatively inexpensive on the market. A simple benchtop filter will suffice in many cases, provided you can stand the sight of it sitting on your bench all the time. You want to look for one that that filters particles down to around 0.5 microns. If you live in an area with fluoridated water you will need to get a twin filter system to deal with that also. NZ filter warehouse have twin filter benchtop systems for less than $300. Many people prefer under bench systems and If you want to be fancy you can get whole house filtration system that cleans the water you shower in etc. If you had the money this would be an ideal option, I don't, so we make do with the benchtop system.One thing to be aware of is that filters that are fine enough to do a good job of removing contaminants can also remove a lot of the beneficial minerals found naturally in water. The solution is to add a pinch of good quality unrefined sea salt to each litre of water you drink. Celtic sea salt or Marlborough Unrefined sea salt are both good options. You just want to add enough to give the water a little mouthfeel, not so much that the water tastes salty. If you are like me and like to liberally salt your food, you can likely skip adding any extra to your water. Athletes and others who lose a lot of sweat should definitely consider adding a pinch of salt to their filtered water to maintain electrolyte and energy levels.As to how much water you should drink, an easy formula is as follows: take your bodyweight in kilograms and multiply by 0.033 to get the amount you should drink in litres per day. For example a if you weigh 75kg, then 75 x 0.033 equals 2.475 or around two and a half litres to get to your daily requirement. Storing your drinking water in glass or stainless steel is ideal, there are now a myriad of good options to choose from, so this should be a no brainer.A couple of final things to note are that if you must drink bottled water, try to keep the bottles away from extremes of temperature and definitely out of direct sunlight. If you are ever stuck somewhere where it is not possible to get bottled or filtered water, then boiling any water you intend to drink will at least get rid of the chlorine.References1. Morris, R. D., Audet, A. M., Angelillo, I. F., Chalmers, T. C., & Mosteller, F. (1992). Chlorination, chlorination by-products, and cancer: a meta-analysis. American journal of public health, 82(7), 955-963.2. Bernard, A., Carbonnelle, S., Michel, O., Higuet, S., De Burbure, C., Buchet, J. P., ... & Doyle, I. (2003). Lung hyperpermeability and asthma prevalence in schoolchildren: unexpected associations with the attendance at indoor chlorinated swimming pools. Occupational and environmental medicine, 60(6), 385-394.3. Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: a systematic review and meta-analysis. Environmental health perspectives, 120(10), 1362.4. Stackelberg, P. E., Furlong, E. T., Meyer, M. T., Zaugg, S. D., Henderson, A. K., & Reissman, D. B. (2004). Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water-treatment plant. Science of the total environment, 329(1-3), 99-113.5. Laville, S. & Taylor, M. (2017 Jun 28). A million bottles a minute: world's plastic binge 'as dangerous as climate change' . Retrieved from https://www.theguardian.com/environment/2017/jun/28/a-million-a-minute-worlds-plastic-bottle-binge-as-dangerous-as-climate-change 6. Wilson, C. (2017, Feb 28). BPA-free water bottles may contain another harmful chemical. Retrieved from https://www.newscientist.com/article/2123098-bpa-free-water-bottles-may-contain-another-harmful-chemical/