The Environment Agency measures water quality of the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of
invertebrates,
angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail. Water quality of the Pillhill Brook in 2019: In 2021 there was concern about water quality after incidents of
sewage discharge by
Southern Water. ==See also==