This study evaluated variations in surface water quality indicators within the rivers and canals of Tien Giang province in the Vietnamese Mekong Delta. Water samples were collected at 34 locations, in the months of March, June, September, and November in 2021. Water quality was assessed through comparison with the National Technical Regulation on surface water quality (QCVN 08-MT: 2015/BTNMT, column A2). The pollution source was forecast using principal component analysis (PCA), whilst the similarity in water quality between locations was evaluated through cluster analysis (CA). Results show that surface waters were contaminated with organic matter, suspended solids, and nutrients. There was clear temporal pattern between rainy season (September and November) and dry season (March and June). PCA analysis predicted six pollution sources of which the three main sources were PC1, PC2, and PC3, explained 59.9% of variation in water quality. The parameters of temperature, biological oxygen demand, chemical oxygen demand, dissolved oxygen, total nitrogen, total suspended solids, nitrite, and sulfate exhibited influence on water quality. The CA results suggest that the 34 monitoring locations can be reduced to 29 locations, which would result in a 14.7% saving in monitoring costs. The results can be used to reevaluate the location and monitoring criteria for surface water quality in Tien Giang province.