We all know that consuming water is important for human survival and health.  In many parts of the world, tap water is considered completely safe.  We simply grab a glass, fill it up from the tap, and drink it down.  

However, not everywhere is so lucky, and there are still a number of places and communities (even within North America or Europe) where drinking tap water can be unsafe.  Below, we outline a few reasons why you may want to think twice about drinking tap water.

If you’ve ever received a notice from your community health authority or water supplier to boil your water, then this article could be especially helpful.

You Want to Avoid Chlorine

Many communities around the world put their water supply through a process called chlorination. The purpose of chlorination is to disinfect the water, ridding it of harmful bacteria, viruses and parasites. Small amounts of chlorine or chloramine are added to the drinking water at a treatment facility, which is then distributed on to you, the consumer.

While the intention is good, problems can arise when too much chlorine is added to your water, as well as chemical by-products that can be created when chlorine reacts with any organic matter.

Specifically, the US CDC asserts that chlorine levels up to 4mg/litre of water are safe, such that negative health effects are unlikely to occur. However, although the EPA regulates this standard in the US, there is no guarantee that all countries in the world follow the same standards. Too little chlorine might mean not enough protection from viruses and bacteria, while too much might lead to more harm than good.

In addition, recent studies have pointed out that chlorine can chemically react with otherwise harmless organic matter in drinking water (eg. decaying plants) to form harmful chlorine by-products. In high enough concentrations, these by-products have been linked to increased risk of developing certain cancers.

The EPA sets maximal concentration levels for these by-products in the US, but why take the risk if you can filter them out? And again, standards in different places may not be as stringent.

Steering Clear of Chemicals

Chemicals are another contaminant that can end up in tap water, depending on the source. We’ve likely all seen the film “Erin Brokovich,” which became so famous because it was based on the true story of the chemical pollution of drinking water by a large corporation in a small community. This was the classic tale of Chromium-6, which led to a wide range of terrible health outcomes for the community that drank the contaminated water.

While certainly not present in all drinking water, you may want to analyze your tap water if your community water source is based near a pulp mill, manufacturing centre, or other industrial/chemical plant. Although chemical pollution of drinking water is rare, when the stakes involve your health and the health of your family, it’s certainly better to be on the safe side.

Read: 5 Reasons to buy a water filter.

Water Borne Pathogens

In some places around the world, tap water is insufficiently disinfected, leaving the possibility of water borne illnesses on the table.  Depending on the source, bacteria, viruses and parasites can all be present in water before it undergoes any disinfection.  

The risk of developing cholera and e. Coli from tap or drinking water are a still unfortunate fact of life for those living in some poorer or underdeveloped countries and communities.  

In what amounts to less severe cases, travellers going to a new country or region may also experience mild gastro-intestinal problems when drinking new tap water.  This is due to a different microbial profile in the drinking water, which your body’s gut is not used to digesting at the time.

Fluoride

Fluoride is another human added chemical compound in most tap water across North America and parts of Europe. The intention is to prevent tooth decay and ensure dental health. In the US, fluoride has been a part of many community water supplies since the 1940s.

However, more recent research has pointed out that all countries have seen a reduction in cavities, not just the ones that use fluoride in drinking water. The proposed reason: the widespread use of other dental hygiene products like toothpaste.

Moreover, early studies suggest that high levels of fluoride exposure can actually damage nerve and brain cells, and has been linked to cognitive deficits like learning and memory problems.

Taste or Smell

Although not necessarily a health issue, having tap water that tastes, smells or looks unappealing can be problematic for those looking to get enough water.  And if we’re avoiding tap water because of preference, that can mean spending more on bottled water or substituting water for not as healthy alternatives.  

If your tap water source is a well or other groundwater, it is possible that it’s saturated with a high mineral content, which can cause it to smell.  For instance, hydrogen sulfide buildup will often make the water smell like rotten eggs or sulfuric.  

And that probably doesn’t sound very appetizing to anyone.

Heavy Metals

Thankfully, excessive levels of heavy metals in tap water is quite rare in many places across the globe. However, it does sometimes occur, even in relatively developed and rich countries like the US.

Many of us know the story of led seeping into the water supply of Flint, Michigan, for example. If not, here is a good recent summary of the events. High levels of lead in drinking water get absorbed into your blood, and can be especially damaging for young children and pregnant women.

In fact, according to the WHO, high levels of lead in blood can lead to serious developmental and cognitive problems, like learning disabilities, behavioral issues and general mental disabilities.

Of course, lead is not the only heavy metal that can show up in tap water. Arsenic is another toxic heavy metal that can occasionally show up in tap water, either through accidental human pollution or its natural presence in some well water.

Among other health concerns, excessive arsenic consumption can result in partial paralysis, skin discoloration, and severe digestive issues like persistent vomiting.

Avoiding Untreated Tap Water

Keep in mind that this list is designed to be helpful for those dealing with a specific situation related to their tap water, and is not intended as a laundry list of reasons to never drink tap water. In many cases across much of the globe, tap water can be perfectly safe.

However, if any of the reasons mentioned sound like something you’re concerned about or are currently dealing with, it might be best to err on the side of caution. When your health and wellbeing is at stake, it makes complete sense to invest in measures like a filtration system or an alternative water source, that can help mitigate or solve your problem.

Read: Which Water Filter Removes the Most Contaminants? How to Choose the Best Filter in 5 Steps.