Sewage discharges on New England waters

What the colours mean

• Advisory in effect solid line on the map

  A sewage discharge on this water is reported as ongoing, or it ended less than the authority's advice window ago (48 hours in most New England wording), or an official advisory or closure is in effect. The authorities' advice is to avoid contact with the water.

  It is not a water-quality measurement. It does not say how much sewage reached a given spot, and the water can carry bacteria for longer than the window.

• Caution dashed line on the map

  The authority's window has passed but the discharge ended less than 72 hours ago, or a discharge with no reported end began in the last 7 days, or a rainfall advisory is posted. Research on sewage-borne illness points to about three days of raised risk.

  It is not an official advisory, and it is not a test result. The 72-hour span comes from the research, not from the authority.

• Unresolved: no end reported hatched yellow on the map

  A discharge here was reported but its end never was. Sources often skip the "ceased" notice, so after the first week the water is shown hatched yellow until 30 days have passed, and the event stays flagged on its pages after that.

  It does not mean the discharge is still running; nobody has said either way. It is shown because a missing end report is itself a reason for caution.

• No current report hollow outline on the map

  At least one source we follow covers this water, and nothing it reports applies right now.

  It is not a finding about the water. Discharges go unreported, reports arrive late, and storm runoff carries bacteria too. Follow posted signs and local health advice.

• Source not updating hatched band on the map

  A source that covers this water has not answered or changed within its usual schedule, so a recent discharge may be missing here.

  It does not mean a discharge is happening; it means we cannot see as much as usual.

• Modeled downstream reach (estimate, not verified by sampling)

  Rivers are not coloured as a whole. A discharge colours a dashed stretch below its outfall, worked out from the river network and the flow at the nearest gauge, coloured by the same rules. A ring marks where the model stops (the tide, a lake, or the distance cap).

Waters drawn without colour are not covered by any source we follow yet. How statuses are worked out.

DirtyWaterWatch shows what public agencies and sewer operators report. A report is not a water-quality test, and the absence of a report does not mean the water is fit for swimming, paddling or fishing. Reports can be late, incomplete or wrong. Follow posted signs and the advice of local health officials.