Selected river systems in the Manila Bay Region(IV-A,III,NCR) discharging into Manila Bay were monitored to determine thier compliance with the water quality guidelines. Interactive Map 1 shows the selected river system monitored.

Inland River

Interactive Map 1. Map showing the selected river system darining into the Manila Bay

At National Capital Region (NCR), there are three (3) river systems (Parañaque, Navotas - Malabon - Tullahan - Tenejeros and Meycauayan - Valenzuela River), fourteen (14) at Region III, and four (4) (Imus, Cañas, Ylang-ylang and Rio Grande Rivers) at Region IV-A. All river systems were already assessed and are being monitored.


Rivers Monitored #Stations Monitored
Parañaque River 10
Meycauayan-Valenzuela River 7
Total: 17


Rivers Monitored #Stations Monitored
Talisay River 3
Angat River 3
Sta. Maria River 3
Obando River 3
Marilao River 5
Bocaue River 3
Meycauayan River 5
Guagua River 3
Pampanga River 5
Hagonoy River 4
Atlag River 3
Labangan River 3
San Miguel River 3
Total: 46


Rivers Monitored #Stations Monitored
Imus River 8
Malimango River 3
Cañas River 6
Rio Grande River 7
Ylang-Ylang River 5
Total: 17

The rivers at NCR and Region III has poor water quality results. Low Dissolved Oxygen level is the result of untreated domestic and industrial waste being discharged to the river. In Metro Manila, only 18% of the population are connected to sewerage system while the remaining population relies on septic tanks inappropriately designed, thus contributing high population load in the waterways.