Aquatic habitats are frequently found to contain polycyclic aromatic hydrocarbons (PAHs), a class of persistent and hydrophobic organic contaminants that pose major ecological and public health risks. Both petrogenic and pyrogenic sources contribute to their presence in surface and groundwater. Once released, PAHs can adsorb onto suspended particles, settle in sediments, and gradually infiltrate groundwater systems, making them challenging to remediate. With special attention to the concentration ranges of polycyclic aromatic hydrocarbons (PAHs), their main congeners, and the degree of pollution seen in various aquatic ecosystems, this chapter offers a thorough overview of global trends in PAH occurrence. Rapid urbanisation, growing industry, and intensive agricultural practices are major factors influencing PAH profiles in surface and groundwater systems, according to source apportionment studies. The long-term persistence of PAHs presents a significant ecological and public health concern because of their well-established carcinogenic, mutagenic, and teratogenic characteristics. In order to stop more contamination and guarantee the preservation of essential water resources, these worries emphasise the urgent need for comprehensive monitoring frameworks, the implementation of cutting-edge water treatment technology, and the enforcement of strict regulatory procedures.