We report on micro-machined flow-rate sensors as part of autonomous multi-parameter sensing devices for water network monitoring. Three different prototypes of the flow-rate sensors have been designed, fabricated and experimentally characterized. Those sensors are made of identical micrometric platinum resistors deposited on different substrates, made of glass, silicon and micro-structured silicon, with and without insulation layers. The sensors are tested under the anemometric operating scheme. They are experimentally characterized under a water velocity range from 0 to 0.91 m/s. We show that the glass substrate device is more sensitive and less power-consuming under identical operating condition. We also show that, when silicon is needed as the substrate material, further optimization and design strategies are required. Experimental results are analyzed with respect to Computational Fluid Dynamics simulations with the Finite Element Method