Water bio-contamination causes serious environmental and economic penalties and health risks in several applications (e.g., freshwater and seawater circuits). In this work, a non-toxic potential strategy able to control this bioburden through new functional bioactive agents, capable of being tethered in polymeric coatings, is presented. Econea biocide was successfully tethered in a silicone-based coating, further used to coat polymeric substrates and monolithic filters. Coated substrates demonstrated promising antifouling effects after being submerged for more than a year in simulated and real conditions. Furthermore, coated monolithic filters showed auspicious growth inhibition and bacteriostatic behaviour for the S. aureus MRSA bacteria.