In recent years, single-use plastic waste such as bags, face masks, and food containers has rapidly increased in lakes and rivers in major Vietnamese cities due to urbanization and deteriorating water quality, causing pollution. Rubbish collection in these lakes relies on manual methods, with workers or volunteers on boats using nets and rakes to scoop surface trash. This approach is inefficient, limited to visible trash, time-consuming, and poses health hazards from harmful odors in polluted areas. The manual method cannot collect waste underwater or in hard-to-reach areas. This paper proposes designing an inexpensive remotely operated vehicle (ROV) for collecting rubbish both on and under the water’s surface. The robot, built with a PVC frame, has three propulsion motors, a radio controller, a surveillance camera, and a high-capacity LiPo battery. It can be easily controlled to move, dive, and float within a range of three hundred meters and a depth of two meters for up to 1 h. Equipped with a compact net-like collection system, the ROV can gather rubbish from deep water layers. It can also monitor illegal discharge pipes and clogged drains to prevent flooding. The robot has been tested successfully in multiple lakes in Hanoi.