The expanding human population and continuing pollution of aquatic resources threaten the survival of life on earth by reducing the quality and quantity of available water. Pollution sources are highly varied but can be categorized as point- and nonpoint source. Point source pollution is highly localized, easily identified, and relatively easily remedied. Nonpoint-source pollution, however, comes from diffuse sources and requires much greater effort to address. Loss of water, oxygen demands, and nutrient effects are examined in detail. Large impacts have been, and are, expected with continued water abstraction. Solutions include litigation and at worst armed conflict. Although oxygen demands from the addition of organic material can be significantly reduced by treating effluents, many parts of the world, especially developing countries, do not have the necessary funds or infrastructure. Significant progress has been made to relieve oxygen demand with in situ methods. These are expensive and require ongoing monitoring and maintenance. Excessive nutrients contribute to eutrophication, loss of oxygen, and ecosystem diversity. The recovery of some significant ecosystems after nutrient reductions is one of the not-so-dim parts of the chapter. Simply preventing aquatic pollution would be the most effective and least costly strategy to deal with it.