The study was carried out to assess the surface water quality in Hau Giang province by applying the Organic Pollution Index (OPI), Water Quality Index (WQI), and Comprehensive Pollution Index (CPI). Water quality data from 48 monitoring locations were obtained from the Hau Giang’s Department of Natural Resources and Environment in 2023. CA was employed to classify water quality in the study area based on the OPI, WQI, and CPI. Pearson correlation analysis was applied to examine the relationships among these water quality indices. Additionally, Principal Component Analysis (PCA) was conducted to identify potential sources influencing surface water quality in the region. The three indices classified water quality into three levels and generally characterized water quality at a medium pollution level. Water quality indices exhibited spatial and temporal variability, with water quality generally deteriorating during the rainy season compared to the dry season. The results of OPI and WQI showed that water quality at locations S16-S20, S35, S37, S38 was in good level. All indices of OPI, WQI and CPI showed good water quality at the locations S35 and S38. Meanwhile, the OPI and CPI indices were similar in assessing the heavily polluted locations including S31, S42 and S47. WQI values only reflected poor water quality at locations S24 and S42. The WQI had a strong negative correlation with the CPI and OPI. Meanwhile, the CPI index had a positive and strong correlation with OPI. The results found the differences in using various indices to reflect water quality in the same study area. PCA revealed that the water quality was affected by two main sources (PC1, PC2) and 4 secondary sources (PC3-PC6). Primary sources explained 60% of the variation while secondary sources explained only 26.6% of the variation. The results of this study showed the necessity of using a combination of WQI, CPI and OPI indices while assessing surface water quality.