Which drinking water is the safest?

Below, we answer several questions about drinking water and trends related to drinking water.

Is Dutch tap water safe?

Yes. Tap water in the Netherlands has to meet very stringent biological and chemical safety requirements, and its quality is safeguarded through regular, strict monitoring. On occasion, the drinking water companies issue a boil-water advisory, for instance in the event of an emergency caused by a broken water main, but this is a rare occurrence.

Naturally, there are factors that present a possible hazard to the quality of our tap water. Examples would include the use of pharmaceuticals, pesticides and personal-care products. And industry discharges waste products, such as GenX, into the rivers. All of these substances end up, via the sewers or as runoff, in rivers or groundwater, which are our sources of drinking water. Climate change can also result in saltier and warmer water. Drinking water companies constantly conduct research in order to anticipate these hazards. Today’s analytical methods are so good that even extremely small concentrations of contaminants can be measured. Here we’re talking about concentrations equivalent to those existing after one paracetamol pill is dissolved in six Olympic swimming pools! Using extra filters at home to make the tap water even cleaner is therefore quite unnecessary. In fact, the filters can actually constitute a threat to the water’s quality, since they’re not always kept properly clean thus facilitating bacterial growth.

Is using rainwater as a source of drinking water better for our health and the environment?

Rainwater is seen as a ‘clean’ source of water. But rainwater often contains low concentrations of pollutants picked up in the atmosphere. That is not the biggest problem however. The surface upon which the rainwater is harvested – a roof for instance –  is often contaminated by animal droppings. Drinking untreated rainwater is therefore a risky business, and it can make people quite sick. If you really want to make drinking water from rainwater, you need to have good disinfectants and carry out (costly) testing. Furthermore, one large-scale treatment process is frequently better for the environment than a whole collection of small treatment installations.

And what about using ‘raw water’?

Health problems can definitely be expected as a result of a dangerous trend that is currently on the rise in the US: ‘raw water’. The proponents of raw water claim that untreated water, which is collected from open, natural sources, is free of all kinds of ‘dangerous substances’ like hormones and fluoride. Here, again, there is a risk of contamination by viruses or bacteria, because for instance the droppings of birds, rats and other animals, or contaminants from a leaking sewer or septic tank, can end up in the water. In 1853, John Snow discovered that a serious cholera epidemic in London was caused by the contaminated water at a public water pump. Since that time safe drinking water has been the object of a great deal of attention. Thanks to a focus on clean water sources and to the large-scale use of disinfectants, average life expectancy in the West has increased dramatically over the last century. Drinking untreated water can be life-threatening. It is for good reason that efforts are made to immediately supply water to people in reception camps in contexts of natural disasters or military conflicts: it is needed to prevent the outbreak of dangerous diseases. And natural sources are not always clean: in 2016, 4000 people in Barcelona fell ill because they consumed water from a ‘clean’ source in the Andorra mountains, which was contaminated with the norovirus from sewage water. What’s more, raw water, at about €15.00 a litre, is extremely expensive. For purposes of comparison: 1000 litres of safe and clean drinking water in the Netherlands costs about €1.50. Raw water is therefore about 10,000 times more expensive than normal tap water.

Are the claims of the proponents of raw water therefore completely false?

Some countries do indeed add fluoride to the water to strengthen tooth enamel. This involves very low, safe concentrations. But this is not legally permitted in the Netherlands, because one cannot give someone something without their consent. And what about the presence of hormones and other substances from wastewater? It is true that all the water we drink has already been used for some other purpose. After all, the total volume of water on earth remains constant. The hydrologic watercycle has existed for millions of years; practically every molecule of water was once drunk by a dinosaur and then urinated. In the Netherlands about one-third of the drinking water is made from surface water, and this water often also contains wastewater. This water was treated before it was discharged, and it is then extensively treated by the drinking water companies. In this manner it satisfies, as mentioned above, stringent requirements and is truly safe.

Isn’t bottled water even safer?

Bottled water is very popular in a number of countries, but in the Netherlands, you don’t need it if you want to drink safe water. Tap water has to meet much more stringent safety requirements than bottled water. Furthermore, bottled water is bad for the environment, because the transport of a single bottle of water requires about 160 litres of fuel. One litre of bottled water is also about 650 times more expensive than a litre of tap water. Of course, bottled water is practical, when we exercise for instance. But it’s both healthier for the environment and your wallet if you simply fill a reusable bottle from the tap.

What do we know about bottled water from the deep sea?

A recent news story reported that Danone was investing in a company that pumps up water from the bottom of the Pacific Ocean near Hawaii. The water is supposed to come from the melted glaciers of Greenland and Iceland. Because of differences in salinity, this water sinks to seafloor and then takes about 1000 years to reach Hawaii. On its journey it’s said to soak up all sorts of minerals and electrolytes, from volcano fissures for instance. The pumped water is then treated with a special technique (reverse osmosis), and then put on sale for about €2.33 a litre. This water is not dangerous to health, since reverse osmosis is a very effective method of removing practically all compounds and microorganisms from the water. The technique is also used in drinking water treatment. Even if we assume that the company’s claims are accurate, and that the water soaks up all sorts of special substances during its long journey over the seafloor, these fantastic ingredients would be removed by the treatment. Why would one then haul this water half way around the planet, and be prepared to pay more than 1500 times more for it than for tap water?

In short: if you want to drink safe water, at a reasonable price and with a low environmental impact, then simply help yourself to a glass of tap water.