Plastic pollution has become one of the most pressing global environmental issues, raising concerns about potential impacts on the environment, organisms and humans. Microplastics (MPs) were found in most water compartments, while nanoplastics (NPs) have recently been detected in environmental samples, thanks to methodological advances. The presence of MP-NPs in urban waters challenges existing systems in ensuring quality of wastewater discharged to the environment and quality of drinking water for human consumption. This book chapter reviews the efficiency of the current treatment systems and provides a general overview of innovative technologies to improve MP-NP removal in the future. It highlights that a decent removal rate can be achieved in general; however, small-sized plastics still bypass the treatments and remain in the water outlet. Newly-developed technologies appear to be promising for solving this problem. Still, they are at the early stage of the development process, therefore, they require further testing and assessments before being deployed in the field.