Water scarcity is increasing rapidly around the world. Water bodies need to be protected from getting polluted and exploit wastewater (WW) as a resource rather than an environmental burden. Disposal and management of WW through biological treatments has been practiced for long but is an energy-intensive and, hence, uneconomical process. However, the use of bioprocesses can significantly reduce these costs, making the management of WW more economically viable. The bio-treatment of wastes of fruits and vegetables, food industry, agricultural wastes, and domestic wastes involves heavy usage of water as a medium (dilutant) for preparing feed for bacteria. The feed consists of 1–5% total solids, and the rest is water. Hence, WW, either as such or after treatment, can act as a resource for bioprocesses such as those leading to the production of valuable bioactive molecules such as polyhydroxyalkanoates (PHA), fatty acids, methane, hydrogen, antibacterials, and enzymes. This can lead to a reduction in waste and WW treatment costs. This review focuses on the potential of WW of diverse origins as a resource for PHA production and improves its economy.