A useful question library on Koh Samui water related issues and on questions about water in general.
What is in our drinking water?
Drinking water, like every other substance, contains small amounts of bacteria. Most of these bacteria are common ones and they are generally not harmful. Chlorine is usually added to drinking water to prevent bacterial growth while the water streams through pipelines. This is why drinking water also contains minimal amounts of chlorine. Water mostly consists of minerals and other inorganic compounds, such as calcium. If you want to find out what substances your tap water consists of and whether it is totally safe to drink you can have a specialized agency check it out for you.
What dangers can there be in drinking water?
There are several problems that can endanger the quality of drinking water. A number of these problems are summed up here.
- Coliform bacteria in drinking water. Coliform bacteria are a group of microrganisms that are normally found in the intestinal tract of humans and other warm-blooded animals, and in surface water. When these organisms are detected in drinking water this suggests contamination from a subsurface source such as barnyard run-off. The presence of these bacteria indicates that disease-causing microrganisms, known as pathogens, may enter the drinking water supply in the same way if one does not take preventive action. Drinking water should be free from coliform.
- Yeasts and viruses can also endanger the quality of drinking water. They are microbial contaminants that are usually found in surface water. Examples are Giardia and Cryptosporidium. Giardia is a single cell organism that causes gastrointestinal symptoms. Cryptosporidium is a parasite that is considered to be one of the most significant causes of diarrhoeal disease in humans. In individuals with a normal immune system the disease lasts for several days causing diarrhoea, vomiting, stomach cramps and fever. People with weakened immune systems can suffer from far worse symptoms, caused by cryptosporidium, such as cholera-like illnesses.
- Nitrate in drinking water can cause cyanosis, a reduction of the oxygen carrying capacity of the blood. This is particularly dangerous to infants under six months of age.
- Lead can enter the water supply as it leaches from copper pipelines. As the water streams through the pipes, small amounts of lead will dissolve in the water, so that it becomes contaminated. Lead is a toxic substance that can be quickly absorbed in the human systems, particularly those of small children. It causes lead poisoning.
- Legionella is a bacterium that grows rapidly when water is maintained at a temperature between 30 and 40 degrees for a longer period of time. This bacterium can be inhaled when water evaporates as it enters the human body with aerosols. The bacteria can cause a sort of flue, known as Pontiac fever, but it can also cause the more serious deathly illness known as legionellosis.
What is Potable Water?
Potable water is water that is considered safe to drink. It has been either treated, cleaned or filtered and meets your local established drinking water standards. Or, it is assumed to be reasonably free of harmful bacteria and contaminants and also considered safe to use in cooking and baking. Examples of potable water would be tap water from treated municipal water systems, or that has been UV filtered, water distilled, or purified by reverse osmosis.
Previously treated potable water can also become contaminated and no longer considered potable or drinkable water.
What is Non-Potable Water?
Non-potable water is generally all raw water that is untreated, such as from lakes, rivers, ground water, natural springs and ground wells. Such water is not considered potable or safe to drink, unless it has passed stringent testing.
Without proper water testing, a body of water carries unknown contaminants and bacteria, and is deemed to be non-potable, unless proven otherwise. Although it may taste fine, drinking such water carries uncertain health risks.
How is tap water supplied in Koh Samui?
To all the houses / villas / apartments offered for rent on Koh Samui, water is supplied in one of three ways:
- Municipal water supply. In different parts of the island’s water quality varies, it depends on the time of year (rainfall-runoff), the state of the pipeline and other factors, sometimes the water can have impurities, discernible odor and unnatural color, for tenants such water is usually free (for home owners it is however not), but sometimes it can be paid for according to the actual flow rate – for the spent cubic meters. Current state tariffs (and they vary from region to region, and the total consumption per month) you can see here.
- Water delivery truck; specially equipped trucks with tanks bring water to houses and fill the water tank at your house, the price is 300-500 baht per car, depending on the needs of the family the owner can take up to 10 of these cars a month.
- Individual wells, the water comes from underground sources, which Samui has a lot of, most often a separate village has a separate well, you can tell that the water comes from a well by a metal tank on the water tower located right in the village. For the villagers, such water is usually free , or the price is fixed at 100-300 baht per one resident. Sometimes the water consumed is considered by the meter. It costs about 30 baht per cubic meter.
Also, an individual well may be located at a detached house / villa. In this case you have to include additional costs for electricity to pump the water. You probably will have to carry it as a tenant.
Despite the fact that the water even in municipal water system may be pure enough for drinking and cooking however it is better to use a special purified water.
What is Reverse Osmosis (RO)?
The reverse osmosis (R.O.) water purification method involves forcing water through a semi-permeable membrane. The membrane filters out minerals such as salt, lead, manganese, iron and calcium, as well as certain chemicals.
While this process is effective at reducing an array of water contaminants, especially fluoride, it does not remove all chlorine and chlorine by-products as well as volatile organic chemicals (VOCs), pharmaceuticals and a wide array of man-made chemicals.
In addition, the process removes naturally occurring minerals in the water that are essential to health, such as calcium and magnesium.
What is Distillation?
Water distillers boil water to collect the steam, leaving behind many contaminants. The steam is then returned to its water form in a purified state.
This water purification method is effective for removing bacteria and most minerals. However, most distillers do not remove VOCs, chlorine and chlorine by-products.
In addition, distillers de-mineralize the water, making it unhealthy to drink.
What is Ultraviolet (UV) Treatment?
The ultraviolet water purification method is highly effective at killing bacteria, viruses, molds, algae, and other micro-organisms including Cryptosporidium and Giardia, two of the most common causes of waterborne illness.
However, because UV systems do not remove most chemical contaminants or sediment, they are not considered effective for drinking-water systems.
This technology is often only used in whole-house water filtration systems and in combination with other technologies.
Many experts believe UV treatment is just as effective as chlorine for killing bacteria and other pathogens. UV treated water is certainly healthier than chlorinated water.
What is Ozone Treatment
Ozone is effectively destroys bacteria and other unhealthy microorganisms in water. It is often used in conjunction with other water purification or water filtration technologies.
It is not effective in reducing levels of chemical contaminants, although some say that it breaks down harmful chemicals into less dangerous molecules.
In Europe, municipal water companies have used ozone technology to treat large quantities of water for many years because of its effectiveness in purifying and conditioning water.
Ozone has been used in Europe for water treatment since early in the 20th century. Its use has been increasing in the U.S. in the last decade, especially since the negative health effects of chlorination have become apparent.
What do the bottled drinking water terms mean?
Beware that many bottled water manufacturers use descriptive terms such as “glacier water” or “mountain spring water,” which may or may not actually identify where the water is from. These are unregulated terms used primarily for marketing purposes.
Thus, it’s important to understand the more common bottled water terms, such as the following:
- Drinking water. This term is used loosely to describe water that is safe for human consumption. It is acceptable for bottlers to use disinfectants (such as chlorine) in amounts considered safe. According to bottled water quality standards, it is also acceptable for bottlers to add fluoride within set limits.
- Well water and artesian water. Both of these waters are tapped through a well, and the water may or may not be treated.
- Spring water. Water from an underground aquifer is collected as it rises to the surface or through a borehole. Water may or may not be treated.
- Ground water. A term used to describe either well water or spring water.
- Mineral water. To be called mineral water, the ground water must contain 250 or more parts per million of total dissolved solids.
- Distilled water. The distillation process involves boiling water, which kills microbes and removes the natural minerals in the water. The steam is then re-condensed and bottled.
- Sterilized water. This water can originate from any source but it has been sterilized and is free from most microbes.
- Purified water. Another water that can come from any source but is free of most chemicals (i.e., no more than 10 parts per million of total dissolved solids). Purified water may also be free of microbes if treated with distillation or reverse osmosis, both of which also remove naturally occurring minerals.