Green Queen Guide: Water Purifiers In Hong Kong 101 – What To Think About, What To Know

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We all know by now that an air purifier is a must for our lovely, but let’s face it, polluted city. However, what about the other necessity of life, aka water? To be honest a water filter is pretty much a must at this point in our Hong Kong eco journey. But given how much a water filtration system can set you back in the $$$ department, we want to arm our dear readers with all the facts you need to make an informed decision about this important purchase. Below, Green Queen gives you a water filter education. As with our air purifier piece, all the information is based on our own in-house research and calculations. 

Why is a water purifier important?

Access to clean water is one of those things most of us take for granted, unless you know one of the 3.4 million people who die each year from waterborne diseases making water the world’s number one killer. In Hong Kong the majority of our water comes from the Dongjiang river in Guangdong and it is processed in 21 treatment plants before it flows into your building. This water is tested and deemed safe for human consumption according to the World Health Organization’s standards. Many older Hong Kongers may be surprised to hear that our city actually gets pretty high marks for its water as in the past citizens were required to boil the water before it was deemed safe to drink. The issue today is not the quality of the water when it leaves the city’s water systems: the problem is what happens to the water when it travels through rusty pipes and old plumbing. Long story short: the city cannot guarantee the quality of the water coming out of the tap. This can cause major contamination such as the scandal in 2015 when lead was discovered in the drinking water at many Hong Kong residential estates and schools.

Many people address concerns regarding water quality by buying bottled water. However, this is not exactly an earth-friendly solution (quite the opposite in fact). Every day in Hong Kong five million plastic bottles are thrown away! This is on top of the carbon footprint of shipping in bottled water from overseas! And let’s not even go into the cost of keeping yourself stocked in bottled water: even if you only spend HKD 5 a day, that’s over HKD 7,000 a year just on water, PLUS the 1,460+ bottles you have tossed. Shameful really…

A water filter can provide you peace of mind while still being kind to mother earth. In addition, it can improve the taste of the water coming out of your tap as there is a small amount of chlorine added (by the city) to prevent the growth of microbes. While this is not harmful it can affect the taste and smell.

What should water filters remove from the water?

Different types of water filters can remove a wide variety of substances that could be lurking in your glass. There are the parasites, such as bacteria, algae, viruses and fungi. In Hong Kong heavy metals such as iron and lead are a leading concern mostly as a result of older plumbing (lead pipes). Beginning in the 1990s, people across the planet started noticing low levels of common medications such as birth control and antibiotics in rivers and even drinking water. Globally, there is growing research and interest regarding the level of pharmaceutical contamination in our water and although there is currently no evidence that the very very low levels of these chemicals (most are removed during treatment just like other impurities) are cause for concern, there have also been no long-term studies on the subject, particularly with regards to the impact on small children.

How should you compare water purifiers?

There are many differences between water filters commonly offered in the market. The first is of course price, which can vary greatly from a few hundred to a few thousand HK dollars. There is also a large range regarding how much water a device can filter and how it is used. In addition to the original sticker price of filters, you will also have to replace your filter cartridge at some point for most of the models on the market. Some of these cartridges can cost over HKD 1,000 so it is important to understand how much each will cost you in yearly maintenance, remembering that the average person in Hong Kong uses 130 liters of water a day.

What are the different models of water filter?

The five common type of water filters to consider:

  • point-of-entry systems: installed where water enters your house and filtering all the water circulation through the house – requires special installation
  • point-of-use system under the sink: attached under your sink at the tap directly – requires installing a special tap install for filtered water
  • point-of-use system countertop: attached to the tap directly and placed on the counter – no special installation required
  • shower/bath filters: usually attached to the shower head- note: usually only removes chlorine
  • free standing gravity-fed: like pitchers or water dispensers, Brita or similar, can sit on countertop – no special installation required but you need to input/fill the water yourself

What does each filter remove?

So what exactly do the filters remove? Not all water filters can remove heavy metals for instance, which is a concern in Hong Kong. That’s why it’s so vital to understand the type of water filter you are investing in and what they can and can’t do. US-based independently organization the National Sanitation Foundation (NSF) have created standards and certifications that show whether a company has put their filters through rigorous standardized testing and meets internationally accepted guidelines. NSF 53 and NSF 58 demonstrate that a filter removes lead, NSF 42 shows it removes chlorine and NSF 401 is a new standard for “emerging contaminants” including pharmaceuticals, herbicides and pesticides, as well as flame retardants and detergents.

What are the common types of water filters?

Activated carbon filters (sometimes called micro filters) are the most common types- think Brita. These use what is basically charcoal that has millions of tiny pores that trap and absorb impurities. These work well for capturing chlorine and organic compounds, which is why it helps to improve taste and odor. They are not good at removing minerals and heavy metals. Many filters on the market today use a series of filters and additional material to remove additional contaminants.

Ion Exchange is used to remove heavy metals, especially lead. Usually this is done using potassium ions and a little bit of chemistry to swap harmful lead for harmless potassium.

Zeolites are similar to a clay and has a special crystal framework that makes it great at filtering water just like a sieve. In addition, zeolites promote natural ion exchange.

Reverse osmosis filters use a concept you may or may not remember from high school biology, aka osmosis, which deals with the passage of a “solvent” aka water through a membrane. Reverse osmosis, sometimes called membrane technology filters, re-engineers this process to force water though a membrane that filters out impurities and most contaminants (including organic compounds, pharmaceuticals and heavy metals). These filters are more expensive and are not as common as the ones mentioned above.

UV radiation filters blast water with very high frequency light that destroys all parasites.

In Part 2 of this series, we review the best home water filter systems available in Hong Kong.

Image courtesy of Pexels (lead).


  • Sonalie Figueiras

    2021 Women of Power, 2019 GEN T Honoree, V Label Global Hero, 2 x TEDx Speaker: Serial social entrepreneur & trends forecaster Sonalie Figueiras is a sustainability expert, food futurist and eco-powerhouse who has been inspiring global audiences for over a decade with practical steps on how to fight climate change. Known as the Green Queen of Asia, she is the founder and Editor in Chief of the award-winning Green Queen - the region’s first impact media platform that educates millions of readers on the connection between health, sustainability and the environment and showcases future solutions. She is also the co-founder and CEO of organic sourcing platform Ekowarehouse and climate tech SaaS Source Green, which helps consumer brands quit plastic packaging thanks to proprietary plastic reduction software. In addition, Sonalie is a global keynote speaker and an advisor to multiple mission-driven startups and NGOs, and a venture partner to several VC funds.

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