For underserved communities around the world, access to clean and safe drinking water continues to be a major challenge. Conventional water treatment techniques are costly, and many communities lack access to such systems, creating a demand for inexpensive, effective, and sustainable filtration technologies. Some other low-cost water purification technologies exist to solve this global problem; this chapter aims to describe some of them targeted to low-income and rural populations. We also describe the potential of specific innovative filtration approaches, including ceramic filters, bio sand filtration, activated carbon and solar disinfection (SODIS), to be both effective and affordable. We also highlight emerging technologies such as nanotechnology-based filtration, membrane filtration with locally available materials, and bio-inspired methods of purification. We particularly focus on community-based methods as well as decentralized water purification systems that enhance the local populace through capacity building and sustainable management practices. It discusses social enterprises and NGOs, government initiatives that support the scale up of these technologies. Well documented case studies from diverse geographical settings are documented data indicating the degree of reduction in occurrence rate of the waterborne diseases as a result of implementing the above solutions. This chapter addresses the technology gap in three aspects of filtration technology affordability, adaptability, and environmental sustainability by showing how innovative but low-cost technologies can help to close the water access gap. The results highlight the importance of interdisciplinary engagement and policy support to further refine and scale these interventions. Ultimately, this study can motive further research and investment in scalable, cost-effective water-filtration technologies for vulnerable groups.