It became possible lately to deploy a full OpenSource application stack for field surveying. This presentation describes a water distribution and waste-water management project from a technical point of view, with a strong integration of mobile tools within an industrialized GIS.This projects features a GIS part, with a centralized reference data storage leveraging PostgreSQL/PostGIS, and uses QGIS as a user interface. This combination allows to manage custom data with high volumes efficiently. The project also includes an important mobile side. Implemented on a rugged tablet, a custom tool has been setup to capture and enrich field data. The software is based on ROAM, a new OpenSource software designed for field survey. The tablet is connected on a 3G/4G network and takes advantage of a GNSS antenna to increase GPS precision. It also features an autonomous offline data management module, so as to be able to work in bad network access conditions. The tablet also embeds all required data for greater efficiency. One specificity of this project is the implementation of a synchronization tool between the data used in mobile situation and the reference data, in a multi-user environment.This synchronization tool, developed with PostGIS and SpatiaLite, let users manage data history, data modifications, data merges, offline mode, as well as branches, for parallel versions of the same data. The latter enables the design of evolution scenarios of the network. A classic issue of the surveying work in mobile situation is therefore solved, being able to work in a disconnected mode with multiple land surveying teams smoothly, while keeping data traceability.The project currently evolves towards water simulation integration, interconnection with SCADA industrial systems, and sensor data automated integration (through webservices).All These components therefore constitute a full software package, fully opensource. The various components can be used for other applications than water management. The new features developed thanks to this project can solve mobile GIS issues, and optimize the TCO of GIS solutions for industrial projects, for real-world critical applications.