Groundwater

Groundwater is replenished or recharged by rain and seepage from rivers. It contributes 14 percent of the total water resource potential of the Philippines. Region X has the lowest potential source of groundwater compared to its surface water potential, while Regions I and VII have the highest potential.

Groundwater is used for drinking by about 50 percent of the people in the country. Based on the water rights granted by the National Water Resources Board (NWRB) since 2002, 49 percent of groundwater is consumed by the domestic sector, and the remaining shared by agriculture (32 percent), industry (15 percent), and other sectors (4 percent). About 60 percent of the groundwater extraction is without water-right permits, resulting in indiscriminate withdrawal. A high percentage (86 percent) of piped-water supply systems uses groundwater as a source.

Source: Philippine Environment Monitor 2003

Water Quality

Pollution of groundwater may come from domestic wastewater, agricultural runoffs, and industrial effluents. This occurs when contaminants reach the aquifer or water table in the form of leachate.

Domestic wastewater is the main contributor of bacterial contamination to the groundwater supplies. The presence of coliform bacteria in drinking water supplies can cause water-borne diseases such as diarrhea, cholera, dysentery, hepatitis A, and others. Limited data on the bacteriological content of groundwater from 129 wells indicated a high level of positive coliform bacteria in 75 wells (58 percent).

Another problem is saline water intrusion, which is caused by over-exploitation or excessive withdrawal of groundwater. This reduces water availability for domestic usage, including drinking and agricultural usage.

Source: Philippine Environment Monitor 2003