Edited sentence: According to the EPA, Billerica's discharges of phosphorus created an overabundance of nutrients.As a result of increased pollutants, major portions of the Shawsheen River are now listed as impaired waters on the 303(d) list of the Clean Water Act.Billerica has recently had problems meeting federal environmental standards along these rivers.Environmental Protection Agency (EPA) and the Massachusetts Department of Environmental Protection (MassDEP) because the town of Billerica exceeded allowable effluent limits for phosphorus, fecal coliform bacteria, pH, and ammonia nitrogen.In June 2001, the Merrimack River Watershed Council (MRWC) also determined that the Shawsheen River failed to meet water quality standards.In May 2007, the town was forced to pay a $250,000 penalty for discharging pollutants into the Concord River.The Shawsheen River and Concord River are the two major waterways within the town.The action was brought by the U.This directly contributed to the excessive aquatic plant growth that now characterizes the river.This situation was largely attributed to stormwater runoff via town, private and state storm drain systems