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Water Quality

Water Bodies. In Naga City, the main river that conveys the surface water to the Bicol river is the Naga river which traverses the urban center of the city. However, the same river comes from the Yabo Sadit and Yabo Grande creeks. The Yabo, Caromatig, and the Langon creeks all together drain into the Naga river.

Located near the headwaters of the Naga River are three (3) accessible waterfalls, namely, the Malabsay, Nabontolan and Secret Falls.

Ground Water Resources. Currently, Naga City is using the groundwater for its drinking and domestic water supply. Apparently, the present safe yield of groundwater is not sufficient with its present demand. Furthermore, with the growing population increase and growing commercialization, water supply is greatly affected. The Metro Naga Waster District (MNWD) is planning to harness the surface water from Yabo river for drinking and domestic consumption for Naga City. When completed, this project would augment the water supply needs of the city.

A 1995 LWUA study on the groundwater within Naga City. Shows an over-extraction of its groundwater resource at 2 M cu.m. per year. Present combined extraction by MNWD and owners of private wells reaches 4.79 M cubic meters. The study plus the annual groundwater recharge at only 2.38 M cu. M. or 49.7 percent of the volume extracted.

Surface Run-off. Studies shows that soil erosions in some parts of the city is attributed to the uncontrolled surface water run-off  from upper barangays, it also contribute to flooding in low-lying areas of Naga City.

To minimize the effect of flooding, the city in conjunction with the various Barangay Irrigators Association has been maintaining Water Harvesting Structures (WHS) at the upper barangays of Cararayan, San Isidro, Pacol and Del Rosario.  These structures like Small Farm Reservoirs (SFR), Small Water Impounding Systems (SWIS) are man-made structures that serve as basin to accumulate surface water run-off from the watershed.  These structures form part of the mitigating measures to control flooding in low-lying areas of the city.

Naga River. Garbage disposal practices along the riverbanks are a major contributory factor in the pollution of the Naga River.  Unabated dumping of solid wastes by residents living along the riverbanks has become inimical to the health of the river.

Currently, surface water from the entire stretch of Naga river is used only for irrigation, recreation, aquaculture and manufacturing purposes along the middle portion of the Naga river watershed.

Water sample studies monitored the areas of Sabang-Tabuco, Dinaga-Lerma-Tinago as the most polluted areas of the Naga River.However, efforts  to contain this problem is being undertaken by concerned agencies with the active participation of barangay councils, NGOs and the private sector.  The Ladies in Green, a local NGO and other members of the Board and partners are assisting the ENRO and the barangay councils in its information and educational campaign (IEC) on the proper disposal of garbage by households located near riverbanks while counterparts in the private sector helps by donating signage and maintenance material to the activity.


Naga River Watershed Area. The Naga River watershed covers 21 barangays of the city and portions of 3 adjoining municipalities.

At its headwaters, the quality of the Naga River is relatively better. But as it flows closer to the urban center, the water’s color changes from crystal clear to almost opaque, reflective of very poor quality, due to abuse and neglect.

Based on the limited data from the eight (8) sampling points along the Naga River, there is an indication that the river is in its critical level during the peak of dry season when there is lesser water flowing through the Naga River.

Watershed Area. At present only about ten percent (564 has.) of the watershed’s total land area (5,445 has.) is forested. This is already a very critical level as indicated by the drying up of some streams within the headwaters of Naga River during summer months.

To address this situation within the city’s watershed area, the ENRO has been conducting regular tree planting/reforestation activities in partnership with the different NGOs, government and private agencies and learning institutions.  Stakeholders are encouraged to participate in said endeavor to further strengthen PAMB in Mt. Isarog.  Also, the DENR has established a field office inside the protected area for easy monitoring of illegal activities, and for the conduct of information and educational campaign for the preservation of endangered flora and fauna.

Naga City Flood Hazard Zone. Low lying areas/barangays in the city suffer perennial flooding during the rainy season. These includes Barangays Abella, Bagumbayan Norte, Bagumbayan Sur, Calauag, Dayangdang, Dinaga, Igualdad, Lerma, Liboton, Mabulo, Peñafrancia, Sabang, San Francisco, Sta. Cruz, Tabuco, Tinago and Triangulo. These affected barangays constitute about 10 percent of the total land area of Naga City.


Naga’s topography places it at the slope of Mt. Isarog, extending downward to the lowland area where the urban center is situated at the foot of Mt. Isarog. The city’s 564 hectares of forest parks and reserves serve as a buffer that ideally absorbs run-off water from the mountain which flows down slopes into the city’s low-lying areas.

Drainage System. Naga’s drainage network has reached a total length of 72,971.70 meters all constructed within the last ten years. This translates to an average of 7,297 meters of new drainage lines constructed per year. The drainage system’s outfall is the Naga River which bisects the poblacion area of the city.

Maintenance. Maintenance of the drainage system is being implemented by the Maintenance Division of the City Engineer’s Office which is manned by 24 personnel.  The maintenance equipment available in the CEO are: dumptrucks, backhoes and manual equipment such as shovels, rakes, hoes and others.  The maintenance personnel are divided into two teams which undertakes maintenance job on a daily routine.

Sanitary Toilets. Of the 22,860 households surveyed, 97.30 percent have sanitary toilets while 634 or 2.70 percent have no toilets at all

Water sealed toilet facilities is used by 95.70 of households.. The remaining 2.70 percent are without any toilet facility, 1.50 percent are using closed pit (Antipolo type) toilet facility.