Freshwater is limited and frequently contaminated by human activity, despite its necessity. Poor sanitation and inefficient agricultural practices exacerbate the situation by putting public health and ecosystems at risk. Thus, monitoring, conservation, treatment, and sustainable management are some essential approaches that must be implemented to ensure long-term access to a clean and safe water supply. Municipal wastewater includes industrial, domestic, stormwater, and infiltration sources, and its composition depends on various factors such as population load, local climatic conditions, urban infrastructure, waste disposal practices, and industrialization. Inadequate wastewater management worsens water pollution and health risks, thus making water surveillance and monitoring an essential measure. This chapter presents an outline of wastewater monitoring processes ranging from conventional to advanced methods, opportunities, and challenges in the wastewater management sector. The conventional chemical monitoring of wastewater includes observations on organic load and toxic chemical presence, while biological monitoring detects microbial contaminants, pollution bioindicators, and the toxicity of certain water contamination on aquatic organisms. Meanwhile, advanced techniques such as membrane filtration, bioassays, and molecular biosensors enhance detection, ensuring effective wastewater management, pollution control, and environmental safety, thus offering cost-effective alternatives to traditional methods. A brief understanding of the above issues is elaborated in this chapter.