Nairobi’s Rainwater ‘Cleaner’ Than Tap and Bottled Water, TDS Meter Reads


Need pure drinking water? The long rainy season in Kenya is the best time for rainwater harvesting. A TDS meter now reads that rain water in Nairobi has the lowest levels of impurities in comparison to other water sources such as tap, bottle, well and borehole.

Using an iSpring TDS meter purchased from merchandise company, water samples collected from rain water sources in Nairobi area recorded an average of 10 parts per million of total dissolved solids. Bottled water samples and tap water samples from affluent areas like the Village Market Shopping complex, Gigiri recorded an average of 40ppm and 50ppm respectively. However, residential tap and shallow well water recorded a whooping 150ppm and 175ppm of total dissolved solids respectively.

Thus, while 10,000 infants in developing nations die as a result of waterborne diseases annually with a recent cholera outbreak claiming lives in various parts of Kenya, switching to rainwater could arguably be an escape route cum preventative measure from waterborne diseases. Alternatively without the need of visiting a laboratory, a TDS meter can estimate how pure the water is or how effective various water treatment methods are by totaling dissolved solids.

In Kenya, recent local media reports indicate that Cholera outbreak in Migori and Homa Bay Counties has claimed at least 10 lives while about 140 individuals were admitted to the Cholera Treatment Center for specialized treatment and observation. And of late, in Kibera, Nairobi, at least 10 people have died with at least 100 hospitalized due to Cholera.

Yet, the recommended World Health Organisation and EPA water purity levels are less than 500 ppm meaning that tap water samples averaging 150 parts per million are still palatable. However, while the TDS meter interprets that one part per million shows that there is one milligram of a certain solid, drinking tap water with 175 ppm would mean drinking 175 mg of different types of unknown organic and inorganic solutes.

The fewer dissolved solids; the purer the water claim manufacturers. However, health experts argue that hard water with higher levels of TDS indicate that there are minerals like potassium and magnesium ideal for human growth and development and eliminating them would mean depleting vital nutrients. On the other hand, other dissolved solids such as, cyanides and heavy metals like lead and cadmium are known to be harmful if not eliminated.

Nevertheless, the number of total dissolved solids can be filtered, distilled, de-ionized or eliminated through reverse osmosis for those concerned about their health. North-Pole magnetizing, boiling or treating water with ozone gas for 20 minutes merely inactivates impurities and anaerobic living organisms without necessarily removing dissolved solids.

To test the effectiveness of various water treatment methods, the pocket size TDS meter uses electronic conductors designed to identify the total dissolved solids of a solution such as concentrated salts and minerals which increase conductivity. The meter tests the conductivity of the solution and estimates the total dissolved solids.

It works by placing an inch of its electrodes without submerging it completely into the water sample. In less than 10 seconds, it typically displays the total dissolved solids in parts per million and occasionally the temperature. One part per million for instance would indicate that there is one milligram of dissolved solids in each kilogram of water.

But despite the TDS meter’s technological functions; the norm of testing water samples in Kenya is by shipping them to any reputable laboratory or water bottling company that has the most accurate method to measure TDS of water. In the lab, the water is evaporated leaving behind dissolved solutes as residue that are later weighed using accurate scales and analyzed with microscopes.

The TDS meter is not readily available in Kenyan supermarkets and electronics’ shopping outlets but can be ordered online.