The study aims to assess the surface water quality in Hau Giang province in 2021 at 44 locations (with a frequency of 5 times per year) using Principal Component Analysis (PCA), Cluster Analysis (CA) and GIS. Surface water quality is compared with the national technical regulation on surface water quality (QCVN 08-MT:2015/BTNMT, column A1) and Water Quality Index (WQI). The results showed that the surface water quality parameters of total suspended solids, organic matters, nutrients, coliform, and Fe far exceeded the allowable limits while the parameter of Cl-, color, and CN- were within the allowable limits of QCVN 08-MT:2015/BTNMT, column A1. The values of WQI showed that the water quality of Hau Giang province ranged from poor to excellent. The water quality at Vam Cai Dau and Hau River areas could only be exploited for water supply, but appropriate treatment is needed. CA divided the monitoring months into three distinct clusters and reduced the sampling sites from 44 to 33 locations, reducing 25% of monitoring cost per year. PCA revealed three main factors which could explain 69.0% of the variation in water quality. The water pollution sources were mainly industrial and agricultural discharges, domestic and urban activities, transportation activities, salinity, hydrological conditions and water runoff. The current findings provide useful information which support local environmental managers and water supply companies for safe and sustainable.