Skip to main content
U.S. flag

An official website of the United States government

Wastewater Indicators

Wastewater Indicators are compounds that indicate the presence of domestic and industrial waste in water sources.These compounds can be useful in understanding the impact of sanitary and storm sewer overflows and the water quality of urban streams.

National Water Quality Laboratory (NWQL) provides sample analysis carried out by chemists, physical scientists, aquatic biologists, and technicians. The Analytical Services (AS) section has broad environmental analytical capabilities to analyze over 800 inorganic and organic contaminants in surface water, groundwater, wastewater treatment influent and effluent, biosolids, suspended sediment, aquatic bed sediment, atmospheric precipitation and aquatic plant and animal tissues.

State-of-the-art techniques are used to make analytical wastewater treatment determinations using approved and custom methods from the U.S. Geological Survey (USGS), Environmental Protection Agency (EPA) and American Society for Testing and Materials (ASTM). The NWQL receives an annual average of almost 40,000 water samples and produces about 1.8 to 2.1 million results. The NWQL analyzes from 70 to 80 percent of all water-quality samples collected by the USGS Water Science Centers, which are located in every State, Puerto Rico and the Pacific Island territories.

Waste Water samples are collected to evaluate the potential role of dissolved constituents in physical or chemical processes that could impede infiltration. A secondary purpose is to identify tracers that could be used to differentiate infiltrated and natural water in the subsurface. Samples of treated effluent and groundwater are collected for a set period of usually several months. Samples collected from the a source are composited over a 24-hour period to account for variations over time. Samples from lagoons and trenches are composited spatially and with depth to account for possible layering or other differences.

NWQL uses the analytical results to discern the basic water chemistry and help USGS scientists understand the fate and transport of a wide variety of contaminants including nutrients, anthropogenic compounds and trace elements in the environment. USGS analytical results are used in determining the long-term effect of these compounds and elements in the environment. For example, the role of nutrients from excess fertilization of agricultural land in the U.S. in the hypoxia occurring in the Gulf of Mexico is mostly due to runoff of nutrients from excess fertilization of agricultural land in the US. Understanding of the distribution and occurrence of trace elements is critical to the determination of water quality to insure that our drinking water and municipal water supplies are safe. These trace level analytical results also provide information on the occurrence, quantities, and distribution of emergent contaminants such as pesticides, steroid hormones, pharmaceuticals and other classes of compounds that are key components of water quality and their potential impacts on human health and aquatic life.