MNWD Assures Tap Water Safe from Covid-19

According to World Health Organization (WHO), waterborne disease remains to be one of the major health concerns globally. With the addition of the Covid-19 outbreak, we cannot help but question the integrity of our water resources and the likelihood of these from getting contaminated.

Early on, WHO declared that while the presence of Covid-19 virus in untreated drinking-water is possible, it has not been detected in drinking-water supplies. Further, other coronaviruses have not been detected in surface or groundwater sources hence, the risk of coronaviruses to water sources is low.

To ensure that our water resources remain safe and free from Covid-19, MNWD has established and maintains a comprehensive and strict source-to-tap water quality monitoring program that covers its entire water supply system – from springs to the waterworks and distribution network. Such method likewise follows the criteria stipulated in the Philippine National Standards for Drinking Water (PNSDW).

Stringent and continuous monitoring – that’s how we ensure clean and safe drinking water straight from the tap. Our laboratory is accredited by the Department of Health (DOH) performing Bacteriological, Physical, and Chemical Analysis with the use of standard laboratory methods and equipment. To know more about our Water Quality methods, here are the key information that you should know:


  1. Water treatment includes Filtration and Chlorination

MNWD applies both processes of Filtration and C hlorination to treat water sources. Filtration is a commonly used, physical, chemical, and in some instances, biological process of water treatment. It involves separation of suspended solids and impurities from water by passing it through porous media. Meanwhile, chlorination is a process where chlorine is added to the drinking-water to kill or inactivate microorganisms, including harmful pathogens. Microorganisms such as bacteria, viruses, and protozoa are killed during the process making tap water fit for direct consumption and proven insusceptible from coronaviruses contamination.
MNWD performs chlorination at any point throughout the water treatment process. Assigned pump operator mixes a certain amount of chlorine granules or liquid chlorine dioxide with water followed by the activation of chlorinator to inject chlorine and water solution in the distribution line. Each point of chlorine application will subsequently control a different water contaminant concern, thus, offering a complete scale of water treatment.

  1. More than 600 water quality tests are completed annually

Every year, more than 600 water quality tests are conducted in MNWD’s laboratory, which is accredited for drinking water analysis to measure various physical, chemical and biological parameters. These tests are regularly being done to our distribution lines, pumping stations, and spring sources. Annual tests for physical and chemical qualities are likewise being administered to pumping stations, spring sources, observation wells, rivers and creeks to capture the entire water tributaries affecting MNWD’s water source.

  1. Daily conduct of Chlorine Residual Test

Essentially, Chlorine Residual Test is part of the monitoring process by MNWD to determine the amount of remaining chlorine in water through the Water Quality Analysis Division (WQAD). Chlorine Residual or the presence of free chlorine in drinking water indicates that:

  • adequate amount of chlorine was added to the water source in order to inactivate the bacteria and some viruses that may cause a health problem and


  • water is safe from recontamination during storage.

The presence of chlorine in drinking water relatively equates to the absence of most disease-causing organisms, as such is a measure of water’s potability.  We take no chances when it comes to water quality issues. In case of a reported dirty water, MNWD immediately deploys personnel for inspection and necessary action.

  1. Minerals Present in MNWD’s Tap Water

MNWD’s tap water is safe and healthy to drink. Choose to drink tap water as it has more stringent requirements for monitoring its quality on a regular basis over other sources. Not only that, tap water contains significant levels of minerals such as:


Minerals Health Benefits
Calcium Build and maintain strong bones
Chromium Regulate blood sugar
Copper Plays a role in energy production
Iron The substance in red blood cells that carries oxygen from the lungs to transport it throughout the body
Magnesium Helps maintain normal muscle and nerve function
Manganese Necessary for normal brain and nerve function
Potassium Helps the muscles contract, regulates body fluids, helps maintain healthy blood sugar and blood pressure levels
Sodium Helps send nerve impulses and affects muscle function
Zinc Needed for the proper growth and maintenance of the human body


  1. Water filters may do more harm than good

MNWD discourages the use of filter devices or cloth filters at the taps. These brownish deposits are due to the minute amounts of minerals inherent in the water supply that were absorbed and oxidised over time. If they are not cleaned or replaced regularly, filters may become a breeding ground for bacteria that may possibly cause health concerns.
In case of a reported discoloured or sandy water, maintenance operations shall be employed such as the flushing of watermains and service pipes.
Given the above information, notably, conventional and centralized water treatment methods which utilize filtration and disinfection, inactivates COVID-19 virus. Further, MNWD maintains adequate stocks of chemical additives and consumable reagents to ensure regular water-quality testing.
At present, there are no indications that COVID-19 is present in the drinking water supply or will ever affect our water sources. Then again, to safeguard public health and prevent Covid-19 contamination to our water sources, MNWD will continue to adhere to the provisions stated in its Water Safety Plan as approved by DOH following the standards of the World Health Organization for water supply operations. (APVSGonzales)


An MNWD personnel from the Water Quality Analysis Division showing the chlorine residual result from the test conducted in one of the water samples using a pocket colorimeter.


Meticulous and systematic — two words that describes how bacteriological testing is being conducted at our in-house laboratory, which also caters to external clients.