A monitoring system and method for any type of fluid system. Exemplary fluid systems include: sanitary and/or storm sewer systems; hydrological power generation, heating and cooling systems; energy exploration, excavation and transmission, specifically hydraulic fracturing known as “fracking”. The system and method utilize chemical sensors and other detection devices, a power source and circuitry to communicate with hand-held devices and/or other local or remote data terminals. Since sewers and other water infrastructure are often used to dispose, transport, store and transform liquids or other materials in addition to human waste and/or waste fluids from other human activity, monitoring effluent and chemical composition of liquids can provide data useful for a wide range of purposes.