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I was looking for a way to ensure safe healthy drinking water. While I am in Bangkok there are options and access to water filters. However, the Chinese in me needed an exhaustive answer. Here I will share my learnings on this elusive answer. There is 2 approach we can look at safe drinking water. The long way is looking at different parameters to measure your current tap water condition and then improve from there. I decide to take the easier method which is to start with the water you get from water filters and work from there. This is because there is no single standard that is agreed upon on what is safe healthy drinking water[9]. Every country has their own definition.

Market available water filters.

Sediment Filter + Reverse Osmosis + Active Carbon Filter + Minerals

The most common filter you see are the ones with 3 cylinders of filters that can be installed under your kitchen sink.

Reverse Osmosis water filter

The second most common ones are the ones you can install on the tap head itself. These ones are commonly Active Carbon Filters. This the one I used while I was doing this research. Toray Vino SX series.

Then you have the tabletop ones which are essentially best of both worlds. Easy to install and maintain and still have enough filter power. If you just want simple drinking water, the simple active carbon filters are enough, you can further boil those water. This is because most modern city tap water has been treated and added with chlorine to kill bacteria and viruses.

The most common filters can be generally grouped into these 4 groups:

  1. Sediment Filter
    • Filters larger particles in water like rust, sand etc. to prevent clogging up your finer particles in the next stage allowing your second stage filters to last longer and only focus on filtering smaller particles.
  2. Reverse Osmosis Filter
    • Superfine filter that will filter up to 0.01 microns. This will filter most particulate including bacteria(2-3microns) but not viruses (<0.001 microns).
  3. Activated Carbon Filter
    • Using adsorption, (like static on your clothes that attracts and sticks dust) Activated Carbon Filters attracts these small ion particles(organic, mineral or chemical) in the water. That is it can filter contaminants like Chlorine, pesticides, lead etc.
  4. Adding Minerals back into the water. (Not available in the tap and table top filters)
    • Add this stage you will have something close to pure water or a.k.a soft water. Soft water is bad for your body because it will absorb minerals from your body. (See Part 2 on why this happens) So at this stage, it is about adding minerals back to neutralize the water, like mineral water.


Important contaminants to think about when purchasing a water filter at home with modern tap water. Meaning look for these in the labels.

  1. Microplastic
    • As long as the filter is smaller than 1Micron it will be able to filter microplastics because the smallest microplastic found is about 1.6 microns.[7] RO filters can definitely filter microplastics.
  2. Virus & Bacteria
    • Yes, Chlorine (which is used by most modern cities’ tap water) kills most viruses and bacteria. However, there is concern about its volatile nature which causes it to disappear too quickly from the water system. So if you are not confident about these. Boiling water at 100 °C for 5-30 minutes will kill most viruses and bacteria. However, boiling water doesn’t destroy bacteria in the form of spores(egg-like) so having a filter that can filter up to 0.1 microns will filter out all bacteria. Viruses are the only ones we cannot be 100% sure about because they are really small and can be heat resistant as well. So in the case of viruses after chlorination, filter and boiling if there are still viruses remaining we will need to deal with them on a case-by-case basis. I won’t cover the final 0.05% of viruses in water in this article.
  3. DBPs

What did I choose in Bangkok

I decided to go with an upgraded Toray Vino table top water filter just because I am renting in Bangkok and would not like to go through the hassle of installing a permanent water filter. The filter is actually better value for money compared to the tap version (SX series seen above.) 8000L for roughly 2000THB compared to the filter for the tap version which is only 600L for 1000ish THB.

Healthy Drinking Water

The main thing about healthy water is ensuring that it hydrates you. It might be obvious but not all water hydrates. Water is absorbed by your body using the osmosis process. If you remember from school osmosis moves water from a solvent that is a higher potential to a lower one. So, if you drink seawater (Hard water) which is very high potential due to the high salt content actually pulls water out of your body and vice versa if you drink pure water (Soft Water) it will pull minerals out of your body because pure water is lower potential than water in your body.

This means healthy water is water that has good minerals in them, hence mineral water. Another important parameter is electrolytes which are the ions found in minerals. Electrolytes[3-6] are important for healthy body functions and are dissolved in your body’s fluid.

What this means is after filtering and attaining clean water(soft water) we need to add back the good minerals back into the water creating whats commonly knows as mineral water.

Minerals / Electrolytes

Important minerals[6] for a balanced potential and electrolytes needed in your water

  1. Sodium
  2. Potassium
  3. Chloride
  4. Magnesium
  5. Calcium
  6. Phosphate
  7. Potassium
  8. Bicarbonates

How to make your own mineral water (Work in progress)

I wanted to keep this as simple as possible since you will do this everyday. So this is still work in progress.

Some of the salts may be tricky to obtain, but the synonyms below may be of some help:

Parameters to measure safe drinking water

Read it in detail here from sensorex[1]

  • 1 Physical Water Quality Parameters
    • 1.1 Turbidity
    • 1.2 Temperature
    • 1.3 Color
    • 1.4 Taste and Odor
    • 1.5 Solids
    • 1.6 Electrical Conductivity
  • 2 Chemical Parameters of Water Quality
    • 2.1 PH
    • 2.2 Acidity
    • 2.3 Alkalinity
    • 2.4 Chlorine
    • 2.5 Hardness
    • 2.6 Dissolved Oxygen
    • 2.7 Biological Oxygen Demand
  • 3 Biological Parameters of Water
    • 3.1 Bacteria
    • 3.2 Algae
    • 3.3 Viruses

Other learnings

Don’t rely on the TDS sensors. The sensor doesnt tell you very much. It just tells you how much stuff is in the water but it doesnt tell you what stuff.

Don’t let dechlorinated water(boiled and Filtered water) stay stagnant for too long bacteria can start growing in the water.











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