Sanitary sewage overflows (SSOs) can pose a risk to drinking water and are linked to boil water advisories (BWAs) which warn residents about potential contamination.
A study in Columbia, South Carolina, from 2013-2017 found that SSOs were associated with a 13% increase in gastrointestinal (GI) illness diagnoses shortly after an overflow event, particularly in predominantly Black neighborhoods.
While BWAs did not generally show a clear link to GI illness, those issued in the winter months (January-March) were associated with higher illness rates compared to advisories issued later in the year.