{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:58:45Z","timestamp":1760147925076,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,3,14]],"date-time":"2023-03-14T00:00:00Z","timestamp":1678752000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FITT S.p.A. (Italy)"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Water leakage is one of main problems of distribution infrastructures, reaching unacceptable peaks of 50% of water lost in old networks in several countries. In order to address this challenge, we present an impedance sensor able to detect small water leaks (below 1 L of released volume). The combination of real-time sensing and such a sensitivity allows for early warning and fast response. It relies on a set of robust longitudinal electrodes applied on the external surface of the pipe. The presence of water in the surrounding medium alters its impedance in a detectable way. We report detailed numerical simulations for the optimization of electrode geometry and sensing frequency (2 MHz), as well as the successful experimental proof in the laboratory of this approach for a pipe length of 45 cm. Moreover, we experimentally tested the dependence of the detected signal on the leak volume, temperature, and morphology of the soil. Finally, differential sensing is proposed and validated as a solution to reject drifts and spurious impedance variations due to environmental effects.<\/jats:p>","DOI":"10.3390\/s23063117","type":"journal-article","created":{"date-parts":[[2023,3,15]],"date-time":"2023-03-15T05:22:59Z","timestamp":1678857779000},"page":"3117","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Pipe-Embeddable Impedance Sensor for Monitoring Water Leaks in Distribution Networks: Design and Validation"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4178-9912","authenticated-orcid":false,"given":"Danilo Aparecido","family":"Carnevale Castillo","sequence":"first","affiliation":[{"name":"Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3485-4317","authenticated-orcid":false,"given":"Marco","family":"Carminati","sequence":"additional","affiliation":[{"name":"Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy"},{"name":"Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, 20133 Milano, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3232","DOI":"10.1073\/pnas.1109936109","article-title":"The Water Footprint of Humanity","volume":"109","author":"Hoekstra","year":"2012","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1186\/s40713-019-0017-x","article-title":"Leak Detection in Water Distribution Networks: An Introductory Overview","volume":"4","author":"Zayed","year":"2019","journal-title":"Smart Water"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"107177","DOI":"10.1109\/ACCESS.2022.3212769","article-title":"A Review on Current Technologies and Future Direction of Water Leakage Detection in Water Distribution Network","volume":"10","author":"Islam","year":"2022","journal-title":"IEEE Access"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1031","DOI":"10.1061\/(ASCE)0733-9429(1992)118:7(1031)","article-title":"Leaks in Pipe Networks","volume":"118","author":"Pudar","year":"1992","journal-title":"J. Hydraul. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Levinas, D., Perelman, G., and Ostfeld, A. (2021). Water Leak Localization Using High-Resolution Pressure Sensors. Water, 13.","DOI":"10.3390\/w13050591"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4210","DOI":"10.1109\/JSTARS.2017.2708817","article-title":"Reliability of Infrared Thermography in Detecting Leaks in Buried Water Reticulation Pipes","volume":"10","author":"Bach","year":"2017","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Sneddon, K.W., Olhoeft, G.R., and Powers, M.H. (2000, January 20\u201324). Determlning And Mapplng Dnapl Saturation Values From Nonlnvasive Gpr Measurements. Proceedings of the 13th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems; European Association of Geoscientists & Engineers, Arlington, VA, USA.","DOI":"10.4133\/1.2922755"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1659","DOI":"10.1140\/epjst\/e2019-800150-6","article-title":"Vibration-Based Leak Detection and Monitoring of Water Pipes Using Output-Only Piezoelectric Sensors","volume":"228","author":"Okosun","year":"2019","journal-title":"Eur. Phys. J. Spec. Top."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.jsv.2003.08.045","article-title":"A Model of the Correlation Function of Leak Noise in Buried Plastic Pipes","volume":"277","author":"Gao","year":"2004","journal-title":"J. Sound Vib."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"6374","DOI":"10.1109\/TIE.2018.2874583","article-title":"Low-Cost, Tiny-Sized MEMS Hydrophone Sensor for Water Pipeline Leak Detection","volume":"66","author":"Xu","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"51965","DOI":"10.1109\/ACCESS.2019.2896302","article-title":"A Review of Vibration Detection Methods Using Accelerometer Sensors for Water Pipeline Leakage","volume":"7","author":"Dziyauddin","year":"2019","journal-title":"IEEE Access"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.measurement.2018.03.018","article-title":"Pipeline Corrosion and Leakage Monitoring Based on the Distributed Optical Fiber Sensing Technology","volume":"122","author":"Ren","year":"2018","journal-title":"Measurement"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"244","DOI":"10.2166\/h2oj.2021.102","article-title":"Application of Fiber Optics in Water Distribution Networks for Leak Detection and Localization: A Mixed Methodology-Based Review","volume":"4","author":"Ibrahim","year":"2021","journal-title":"H2Open J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.ndteint.2013.10.007","article-title":"Time Domain Reflectometry, Ground Penetrating Radar and Electrical Resistivity Tomography: A Comparative Analysis of Alternative Approaches for Leak Detection in Underground Pipes","volume":"62","author":"Cataldo","year":"2014","journal-title":"NDT E Int."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1061","DOI":"10.1088\/0957-0233\/12\/8\/311","article-title":"Electrical Resistance Tomography to Detect Leaks from Buried Pipes","volume":"12","author":"Jordana","year":"2001","journal-title":"Meas. Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"D\u2019Adda, I., Battaglin, G., and Carminati, M. (2021, January 22\u201328). A Low-Cost Flexible Pipe Sheath for Multi-Parameter Monitoring of Water Distribution. Proceedings of the 2021 IEEE International Symposium on Circuits and Systems (ISCAS), Daegu, Republic of Korea.","DOI":"10.1109\/ISCAS51556.2021.9401738"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"8859742","DOI":"10.1155\/2021\/8859742","article-title":"Interdigital Capacitive Sensor for Cable Insulation Defect Detection: Three-Dimensional Modeling, Design, and Experimental Test","volume":"2021","author":"Luo","year":"2021","journal-title":"J. Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"114145","DOI":"10.1016\/j.sna.2022.114145","article-title":"Electrically Functional Water Sensing Duct Tape Suitable for Detection of Indoor Pinhole Leakages with High Spatial and Temporal Resolution","volume":"351","author":"Quan","year":"2023","journal-title":"Sens. Actuators A Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1438","DOI":"10.1109\/TBCAS.2017.2748158","article-title":"Miniaturized Impedance Flow Cytometer: Design Rules and Integrated Readout","volume":"11","author":"Carminati","year":"2017","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Carminati, M., Mezzera, L., Turolla, A., Pani, G., Tizzoni, M., Di Mauro, M., and Antonelli, M. (2019, January 26\u201329). Flexible Impedance Sensor for In-Line Monitoring of Water and Beverages. Proceedings of the 2019 IEEE International Symposium on Circuits and Systems (ISCAS), Sapporo, Japan.","DOI":"10.1109\/ISCAS.2019.8702662"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Riboldi, C., Castillo, D.A.C., Crafa, D.M., and Carminati, M. (2023). Contactless Sensing of Water Properties for Smart Monitoring of Pipelines. Sensors, 23.","DOI":"10.3390\/s23042075"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1039\/B612866A","article-title":"Characterization and Optimization of Liquid Electrodes for Lateral Dielectrophoresis","volume":"7","author":"Demierre","year":"2007","journal-title":"Lab Chip"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"10906","DOI":"10.3390\/s120810906","article-title":"Novel Fiber Optic Sensor Probe with a Pair of Highly Reflected Connectors and a Vessel of Water Absorption Material for Water Leak Detection","volume":"12","author":"Cho","year":"2012","journal-title":"Sensors"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"108479","DOI":"10.1016\/j.measurement.2020.108479","article-title":"Sensitivity of Water Meters to Small Leakage","volume":"168","author":"Pietrosanto","year":"2021","journal-title":"Measurement"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"649","DOI":"10.2166\/hydro.2013.019","article-title":"Model-Based Leak Detection and Location in Water Distribution Networks Considering an Extended-Horizon Analysis of Pressure Sensitivities","volume":"16","author":"Cayuela","year":"2014","journal-title":"J. Hydroinform."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1186\/s43065-021-00021-6","article-title":"Machine Learning Model and Strategy for Fast and Accurate Detection of Leaks in Water Supply Network","volume":"2","author":"Fan","year":"2021","journal-title":"J. Infrastruct. Preserv. Resil."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/6\/3117\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:55:03Z","timestamp":1760122503000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/6\/3117"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3,14]]},"references-count":26,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2023,3]]}},"alternative-id":["s23063117"],"URL":"https:\/\/doi.org\/10.3390\/s23063117","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2023,3,14]]}}}