[1] Its watershed area covers Calamba in Laguna and the municipalities of Santo Tomas, Tanauan, and Malvar in Batangas.

[2] In the December 2005 LLDA Water Quality Status Report, the San Juan River was listed as "worse than Class D" with a very low percentage of dissolved oxygen saturation.

"Worse than Class D" means that the San Juan is not usable for any of these functions.

[3] The LLDA's conservation efforts for the major tributaries and watersheds of Laguna de Bay have led to the creation of the Laguna de Bay River Basin Councils, of which the MTSC-San Juan River Protection Fdn., Inc. is particularly tasked with the conservation of the San Juan.

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