Water Quality Data Monitoring and Analysis: This dataset provides information about surface water quality of streams and rivers in the Maziba catchment, Western Uganda. Water quality data was collected monthly from 16 selected sites (streams and rivers) across the Maziba catchment over one year (July 2023–June 2024). Sites were carefully selected considering land use intensity and accessibility. On-site measurements of physicochemical parameters - water temperature, electrical conductivity, dissolved oxygen, and pH—were conducted according to APHA (2017) guidelines. A handheld pH and EC meter (HI98130) measured temperature, pH, and electrical conductivity, while a DO meter (PDO-519 model) assessed dissolved oxygen. Other physicochemical parameters were analysed the National Reference Laboratory in Entebbe (Uganda) collecting water samples (1-litre plastic bottles). Water quality parameters include, Temperature (°C), Dissolved Oxygen (mg/L), Turbidity (NTU), Chla (µg/L), pH, Conductivity (µS/cm), Total dissolved Solids (mg/L), Total Hardness (mg/l), Sodium (mg/L), Potassium(mg/L), Nitrite -Nitrogen(mg/L), Ammonium-Nitrogen (mg/L), Chloride (mg/L), Sulphates(mg/L), SRP(mg/L), Total phosphorus (mg/L), Nitrate-Nitrogen, (mg/L), Total Nitrogen (mg/L) and Total Suspended Solids (mg/L). Provided Data: The README_overview_maps.pdf document provides a extented description and overview maps (topography, land cover, sampling sites) Water Quality Data for all sites and total period is provided in this file "SurfaceWaterQualityData_Maziba.xlsx" Attributes of the Water Quality sampling sites and features of the corresponding sub-catchments are given in the file "Catchment_SamplingPoint_Attributes.xlsx" The zipped folder (SurfaceWaterQualityData_Maziba_shapefiles.zip) contains GIS - Shapefiles of the sampling sites, river network and sub-catchments Funding: The dataset is prepared within the project “P082 Land Use and Land Cover Change Effects on Water Quality Characteristics of the Maziba Sub-Catchment, Western Uganda | MaziWa”. The project aims to contribute to the understanding and sustainable management of water quality and water resources in southwestern Uganda. The project is led Kabale University, with the BOKU University, Vienna as partner. The project is supported by the Africa-UniNet, which is financed by the Austrian Federal Ministry of Education, Science and Research.