The presence of antibiotic-resistant bacteria in our environment is a matter of growing concern. Consumption of contaminated drinking water or contaminated fruit or vegetables can provoke ailments and even diseases, mainly in the digestive system. In this work, we present the latest data on the ability to remove bacteria from potable water and wastewater. The article discusses the mechanisms of the antibacterial activity of polymers, consisting of the electrostatic interaction between bacterial cells and the surface of natural and synthetic polymers functionalized with metal cations (polydopamine modified with silver nanoparticles, starch modified with quaternary ammonium or halogenated benzene). The synergistic effect of polymers (N-alkylaminated chitosan, silver doped polyoxometalate, modified poly(aspartic acid)) with antibiotics has also been described, allowing for precise targeting of drugs to infected cells as a preventive measure against the excessive spread of antibiotics, leading to drug resistance among bacteria. Cationic polymers, polymers obtained from essential oils (EOs), or natural polymers modified with organic acids are promising materials in the removal of harmful bacteria. Antimicrobial polymers are successfully used as biocides due to their acceptable toxicity, low production costs, chemical stability, and high adsorption capacity thanks to multi-point attachment to microorganisms. New achievements in the field of polymer surface modification in order to impart antimicrobial properties were summarized.