Compact digital TDS meters, commonly known as water-testing pens, are increasingly finding their way into households in the federal capital as consumers show growing interest in checking the quality of drinking water and monitoring the performance of domestic filtration systems.
TDS testing pens gain popularity in Islamabad amid water-quality concerns
Hina Durrani
ISLAMABAD, Sep 02 (APP):Compact digital TDS meters, commonly known as water-testing pens, are increasingly finding their way into households in the federal capital as consumers show growing interest in checking the quality of drinking water and monitoring the performance of domestic filtration systems.
The pocket-sized devices, which can provide a Total Dissolved Solids (TDS) reading within seconds, are being widely marketed through online shopping platforms in Pakistan, with prices of basic models generally ranging from around below Rs1000 to Rs2,000, while more advanced multi-function devices cost more.
The increased consumer interest comes as households increasingly rely on filtration plants, bottled water and reverse-osmosis (RO) systems and seek convenient ways to monitor their water.
A TDS meter measures the estimated concentration of dissolved substances in water, including salts and minerals, and generally displays the reading in parts per million (ppm). Consumers can use the device to compare water from different sources or monitor changes in the performance of an RO or filtration system.
However, water-quality specialists caution that a TDS reading should not be confused with a complete test of drinking-water safety. TDS indicates the amount of dissolved material but does not identify individual substances.
A handheld TDS meter cannot establish whether water contains bacteria, viruses, pesticides, arsenic, lead or other specific contaminants, as the device only indicates the concentration of dissolved salts and minerals and cannot detect several harmful contaminants.
Talking to APP, Director National Water Quality Laboratory, Pakistan Council of Research in Water Resources (PCRWR), Saiqa Imran said TDS was only one of several parameters used to assess water quality and could not detect contaminants such as arsenic, nitrate, fluoride, heavy metals or disease-causing microorganisms.
“Even if water has an ideal TDS level of 300 or 500 milligrams per litre, it may still be unsafe if it contains arsenic, nitrate, fluoride, heavy metals or microbial contamination.”
She said the TDS meter could be used as an initial screening tool to determine the approximate level of dissolved salts and minerals, but laboratory testing was necessary to establish the safety of drinking water.
According to her, water could contain bacteria or viruses even when its TDS level was within the permissible range.
Similarly, the presence of arsenic, nitrate or other chemical contaminants could not be determined through a TDS concentration. She said PCRWR recommended testing water for relevant parameters according to the contamination risks of a particular area.
“In Rawalpindi and Islamabad, nitrate testing can be important, while arsenic, fluoride and other parameters may require greater attention in areas where these contaminants are known to occur,” she said.
The expert also cautioned consumers against assuming that an extremely low TDS concentration represented the highest quality water.
She said household reverse osmosis (RO) systems could remove dissolved minerals from water, and consumers sometimes mistakenly considered a very low TDS concentration proof that their water was exceptionally pure.
A TDS concentration of 20, 30 or even 14 milligrams per litre, however, should not automatically be considered an indicator of superior drinking water, she added.
Saiqa Imran urged consumers using domestic filtration systems to understand what their equipment actually removes and to have their drinking water tested periodically by a qualified laboratory.
She said greater public awareness was needed because many consumers were being provided with TDS meters along with RO systems without adequate information about their limitations.
“TDS is not the only criterion for determining water safety. It only tells us about the dissolved mineral and salt content,” she said.
She stressed that laboratory analysis remained essential for confirming whether water met the applicable drinking water quality standards.
