BAGUIO City Building and Architecture Office head Nazita Bañez ordered the demolition of 20 pigpens near the Buyog Watershed, believed to be affecting the water table inside the reservoir.
Bañez said owners of pig pens were already given notice.
"We were informed by the Baguio Water District regarding the pig pens, which contaminate the water source," Bañez said, but the official has yet to establish how long these pigpens were operating.
The city official added owners of the pigpen were already given a 15 day period to remove the illegal structures.
"The problem is the contamination of the water from several small pig pens," Bañez added citing an ordinance which prohibits hog raising near watersheds and residential areas.
"It is not even allowed in the ordinance to raise pigs in the city of Baguio," Bañez ended.
Last year, residents near the Buyog Watershed and some environmental groups have called for the protection of the watershed after informed that pigpens were raised in the area.
Reports said a large portion of the 20-hectare Buyog is inhabited by residents of Pinget, Quirino Hill and other barangays straddled by the forest reserve. Pinget barangay officials sought the segregation of 113,193-square-meter area occupied by residents for housing as early as 2009.
Buyog Watershed is one of the watersheds supplying water, aside from the Busol.