Water is one of the most crucial parts of human life as it is one of the most critical substances in human's life. With how limited the published information regarding water quality issues around us, there needs to be a platform for people to access this kind of information. Therefore, a Geographic Information System (GIS) will be build to map every observation points in Pontianak and use the observations data to calculate water quality status using STORET method based on Ministry of Environment and Forestry Ministerial Decision No. 115 of 2003 concerning Guide to Determine Water Quality Status. The method was calculated by comparing the water quality data with quality standards which are regulated in Government Regulation No. 22 of 2021 concerning Maintenance of Protection and Management of Environment. Which then scored and classified using US-EPA (Environmental Protection Agency) classification system based on the total score of each observation point. The result showed that from the data in Pontianak in 2021 there were 8 observation points classified as moderately contaminated, 18 observation points classified as highly contaminated, while 68 observation points did not have enough data to calculate. As to the result of system interface testing using an online questionnaire that was given to 51 respondents generated a result of 89,1% using Likert Scale which can be classified as a very good testing result.