Visiting Angat and Ipo Dams and Maynilad’s La Mesa Water Treatment Plants

The breathtaking view of Angat river greeted us morning of February 28, 2020 when we visited this concrete water reservoir, Angat Dam as part of our field, educational tour hosted by Maynilad. It’s been a decade since the last time I visited Angat river. I live in Sta. Maria back then and I was starting Woman in Digital blog in 2010. I’ve wanted to feature the heritage sites and beautiful churches in Bulacan, hop on a tricycle and found a hidden place called Bakas in Norzagaray. I think aside from the footprints of Bernardo Carpio, there are more important structures you’ll find in Norzagaray and these are the Angat and Ipo dams that supplies Metro Manila and nearby provinces with water.

Angat View Deck
Angat View Deck

When I received the invitation to explore Maynilad’s treatment plants, I immediately said yes because we are customers of Maynilad. It would be great to learn more about the products and services we place our trust in.

Angat Rainforest and Eco Park (AREP)
Angat Rainforest and Eco Park (AREP)

To get a bigger picture and understanding of Maynilad Water Services, Inc., they showed us their huge facilities. From Quezon City, we traveled about two hours to Norzagaray where Angat dam is located. I’m glad that traffic was just okay considering it’s a Friday. I almost fell asleep when suddenly I noticed we’re on the zigzag road. I opened my eyes and felt relaxed to see lush greens and tall trees. They say it’s the area in Norzagaray known as “hilltop”.

Finally, we reached Bitbit bridge. There are locals swimming at the beautiful Bitbit river. Across the Bitbit bridge is a huge sign that tells us we’re entering Angat Rainforest and Eco Park (AREP).

Angat Dam Tour
Engr. Rodel Tumandao, Head of Water Source of Maynilad

A Closer View of Angat River

It was my first time seeing Angat Dam closer. I only see it in the news. I feel fortunate to get a closer look with our dam. From the viewing deck, you will get a picturesque view of Angat river and the Angat dam. The strong wind, blue sky and river reminds me of the power of nature.

Angat Dam in Norzagaray
Angat Dam in Norzagaray
AREP used to be a public place until it was privatized and closed to the public. Engr. Rodel Tumandao, Head of Water Source of Maynilad, explained the privatization and provided information about Angat dam. He also led the tour. Maynilad serves the West Zone of the Greater Manila area. It is the largest water concessionaire in terms of customer base in the Philippines.

Angat River
Angat River
There are four uses of Angat dam - water supply, irrigation, power as hydro and for flood control. Angat dam helps prevent flooding in the downstream portion of Bulacan in case there's an out-pour of rain water.

The watershed is 62,000 hectares. About 97 percent of water supply in Metro Manila comes from Angat dam. The operating level is between 180-212 meters. The dam structure has a hydropower plant.

Water Allocation in Metro Manila. Why Do We Experience Rotational Water Service Interruptions?

There is an inter-agency group that discusses the water allocation of every stakeholders - MWSS for domestic water supply, NIA for irrigation, and the Luzon Clean Water Development Corporation servicing the entire Bulacan.

Save Water, Save the Future
Maynilad source raw water supply from Angat Dam

About 91% of Maynilad’s raw water supply comes from Angat Dam in Norzagaray. The rest comes from Laguna Lake. At the moment, there is a 14% reduction in raw water allocation for MWSS so the Metro Manila water concessionaires, including Maynilad, is forced to implement daily rotational water supply interruption. This is to ensure that all consumers will still have water supply daily, even if not 24hours.

Based on the protocol, once water level reaches 180 meters, the National Water Resources Board (NWRB) starts prioritizing domestic water supply (for MWSS), and nothing goes to irrigation (for NIA). But in June 2019, water level in Angat Dam went below 160 meters, which is the critical level. This is when we started experiencing rotational water service interruptions.

Ipo Dam in Bulacan
Ipo Dam in Bulacan
Whenever the allocation for the water concessionaires is reduced, they are forced to implement rotational water service interruptions kailangan kasing pagkasyahin sa lahat ng customer yung available na supply.

At present, although water level in Angat Dam is at 201 meters (as of March 6, 2020), this is still not an ideal level, particularly because the dry season is coming (less rains but higher demand  for water because of the heat). To address this foreseeable problem and to ensure that there will still be available raw water supply come summer, the NWRB continues to implement the reduced raw water allocation for MWSS.

To help mitigate the impact of the reduced water supply, Maynilad presented to us their action plans, some of which were already implemented.

Maynilad’s Action Plan, Solutions to Long Term Water Crisis

Maynilad built its Putatan Water Treatment Plant in 2010, which treated raw water from Laguna Lake using state-of-the-art technology. This was the first time for any water company to convert raw water from Laguna Lake into drinking water. This facility produced 150 million liters of water per day.

Visiting La Mesa Water Treatment Plants

In 2019, Maynilad built a second water treatment plant that also gets raw water from Laguna Lake, adding another 150 million liters per day to the water supply. Currently, Maynilad has an ongoing bidding for its Poblacion Treatment Plant, which will be its third facility to draw water from the lake.
Maynilad is also looking at the possibility of getting additional water from rivers in Cavite within its concession area using modular treatment plants. Hopefully, it will add another 27 million liters per day of water.

Finally, Maynilad is also tapping deep wells that will contribute around 52 million liters per day of additional supply, which will be important this summer time. Note, however, that long- term use of deep wells is not advisable, as it leads to land subsidence. Maynilad has only been issued a temporary permit by the NWRB to reactivate some deep wells to help augment the current supply deficit from Angat and Ipo Dams.

Visiting the Maynilad’s La Mesa Treatment Plants

We started and ended our tour at the La Mesa Water Treatment Plants 1 and 2 located in Greater Lagro, Novaliches Quezon City. This facility processes raw water from Angat Dam into clean, reliable and safe drinking water before it reaches our homes.

Visiting La Mesa Water Treatment Plants

If you’re interested how raw water is treated, from Angat Dam it goes through a multi-stage treatment process that includes:

  1. Screening where raw water passes through screens that prevent the entry of foreign objects such as grass, leaves and tree limbs. 
  2. In the Rapid Mixing stage, chemicals are added to the raw water so that undesirable solids will form into clusters. 
  3. Flocculation is the next step where raw water is gently stirred so that small clusters of suspended solids will collide and form into large particles called “flocs”.
  4. Sedimentation where floc particles get heavier and settle to the bottom of the basin.
  5. Filtration is the 5th stage in the treatment. Water from the sedimentation basins is filtered through dual-media filters. These filters trap the flocs or the big particles as water flows down through them.

Maynilad also does the post treatment procedure before water reaches the reservoirs down to the mini boosters and pumping stations. In this stage, they add chlorine to disinfect water and make sure that it’s safe to use by the consumers. Lime is also added to correct the pH or acidity levels of the water. With this, it prevents corrosion of the pipes during the distribution process.

Disinfection with Chlorine

Sometimes, we think that there’s too much chlorine in the water coming out from the faucet but Manilad explained why chlorine is needed in treating water. Chlorine makes water potable and safe to use. Assuring us that it is within the safe level but if you’re still in doubt, I suggest allowing water to run from the faucet, especially when water resumes after hours of interruption.

Starbucks Cherry Blossom Water Bottle
Save water today! Brought my Starbucks Water bottle to this trip.
Customers can also report too much chlorine, leaks and illegal water connection by calling the Maynilad hotline at 1626 or visiting their website. Maynilad has over 1,000 water sampling points from Valenzuela to Cavite City. Every month, water samples are collected from these points for physical, chemical and bacteriological examination. This is to ensure that water in the West Zone is potable.

Ipo Dam
Grateful that we have safe water to use, everyday!

Overall, the tour provided insights on the current situation of our water supply. The message was clear and that is to save water the best possible way we can. Water is important to life. There is no other substance humans need than fresh water. Without water we can only survive a few days. I could just imagine piling up laundry clothes and dirty dishes because we do not have water supply. I appreciate the efforts that Maynilad has been doing especially by informing consumers of the water interruption schedules. Ensuring the following day that water supply resumes. The shortage will be felt until summer of this year so we must conserve water now.


  1. yes miss marj need natin din magtipid ng tubig lalo na papalapit na ang summer season mas need ng tubig sa panahon na ito at laking tulong talaga ang maynilad para sa atin mga consumers ginagawa ang lahat maibigay lang ang tubig na need natin sa araw araw.


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