Editing Biochemical oxygen demand (section)

=== Typical values ===
Most pristine rivers will have a 5-day carbonaceous BOD below 1&nbsp;mg/L. Moderately polluted rivers may have a BOD value in the range of 2 to 8&nbsp;mg/L. Rivers may be considered severely polluted when BOD values exceed 8&nbsp;mg/L.<ref>{{cite book |last=Connor |first=Richard |title=The United Nations World Water Development Report 2016: Water and Jobs, chapter 2: The Global Perspective on Water |publisher=UNESCO |date =2016 |location=Paris |page=26 |isbn=978-92-3-100155-0}}</ref> Municipal [[sewage]] that is efficiently treated by a [[sewage treatment|three-stage process]] would have a value of about 20&nbsp;mg/L or less. Untreated sewage varies, but averages around 600&nbsp;mg/L in [[Europe]] and as low as 200&nbsp;mg/L in the U.S., or where there is severe [[groundwater]] or [[surface water]] [[infiltration/inflow]]. The generally lower values in the U.S. derive from the much greater water use per capita than in other parts of the world.<ref name="Sawyer" />