DirtyWaterWatch Public waters. Public record.

New York / Waters /

Tappan Zee

River in New York, past Irvington, Nyack, Ossining, Piermont, Tarrytown and Upper Nyack

Current status

No current status shown

No current status is assigned to this water outline. Check the water page for reports and any estimated downstream stretches. Why this status, and its source

This badge describes the water outline. Check the downstream stretches on the map and below for discharge statuses.

Map sources: water outlines and launches from OpenBoatLaunch and OpenStreetMap contributors (Open Database License); wastewater outlets from EPA and state records; downstream estimates by DirtyWaterWatch using U.S. Geological Survey maps and flow data. Base map: OpenFreeMap and OpenMapTiles.

Square boat markers mark boat launches listed by OpenBoatLaunch. Outlined boat markers are marinas and clubs: not public access.

Bookmark this water page and check it before each trip · Report a missing notice or error

About this status

Why this status: No current status: no report we track sets a status on this water outline now.

How long each status lasts, and why

Sources checked: NY DEC Sewage Pollution Right to Know (last successful check 2026-11-02 21:20 UTC). Status by DirtyWaterWatch, updated 2026-11-02 21:26 UTC.

No status does not mean the water is safe. Follow posted signs and local health advice.

Updated .

Estimated downstream stretches on Tappan Zee

No downstream stretch has a current status here as of Nov 2, 2026, 4:26 PM EST. Check the reports below.

The last 90 days

Last 90 days, hour by hour. Red: discharge or advisory reported. Amber: caution. Hatched amber: end not confirmed. Grey: no current status on the water outline. Purple hatching: source update overdue.
  • End not confirmed: to
    1 report: Orangetown 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Orangetown 1
    Show records

    The records are also in the report table on this page.

Source: DirtyWaterWatch calculations using the reports named above and the published status rules. Updated 2026-11-02 21:26 UTC.

Reported discharges over time

  • Discharges affecting the Tappan Zee in New York, last 12 months55 affecting this stretch: 5 reported in New York, none arriving from upstreamDecember 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once. Arriving discharges are estimated from modeled downstream reaches.
  • Days with a discharge affecting the Tappan Zee in New York, last 12 months5Reported on the Tappan Zee in New York: 5 · Arriving from outfalls upstream, estimated: 0December 2025 to November 2026A day counts once however many discharges were under way on it. Verified reports where available, else notices; revisions and duplicates counted once.
  • Hours with a discharge or advisory status on the Tappan Zee in New York, last 12 months336Reported on the Tappan Zee in New York: 336 · Arriving from outfalls upstream, estimated: 0December 2025 to November 2026Red hours by the map's rules: each discharge to its reported end plus the state's post-discharge period; overlapping hours count once.
  • 2026 season with a discharge or advisory status on the Tappan Zee in New York3.8%May to October 2026Share of May 1 to October 31 hours with red status by the map's rules, of the hours a source covered.
  • Records behind the last-90-days strip for the Tappan Zee in New York1Reported on the Tappan Zee in New York: 1 · Arriving from outfalls upstream, estimated: 0last 90 daysEvery distinct record the strip lists for its red, yellow and unresolved hours, notices and unresolved reports included; counted as the strip counts them.

Combined sewer overflow (CSO): sewage mixed with rainwater spills from a shared sewer system. Sanitary sewer overflow (SSO): sewage spills from a sewer meant to carry sewage separately from rainwater. Treatment bypass: wastewater skips one or more treatment steps. Blended discharge: wastewater that skipped some treatment is mixed with treated wastewater. Outfall: a pipe or outlet where wastewater enters a water body.

Reported discharges per month

5 reported discharges, January 2022 to November 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Treatment bypass, blended or other

Source: ny-dec-sprtk. Records cover January 1, 2022 to November 2, 2026.

Show table

Hours with a discharge or advisory status per month

Hours when this water had a discharge or advisory status under DirtyWaterWatch rules.

  • Discharge or advisory reported

3 discharge reports have no end time and are not marked ongoing; under DirtyWaterWatch rules they show caution, not a discharge or advisory status, and add no hours here.

Source: ny-dec-sprtk. Records cover August 11, 2021 to November 2, 2026.

Show table

Days with a reported discharge per month

A day counts when any counted discharge was under way on it, from its start to its reported end in Eastern Time; a report with no end counts its start day.

Source: ny-dec-sprtk. Records cover January 1, 2022 to November 2, 2026.

Show table

Reported discharges per year, 2021 to 2026

5 reported discharges, 2021 to 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Treatment bypass, blended or other
  • Incomplete source coverage
Limited records

Source: ny-dec-sprtk. Records cover August 11, 2021 to November 2, 2026.

Show table

Hours with a discharge or advisory status per year

Hours with a discharge or advisory status each year under DirtyWaterWatch rules; 2026 to date.

  • Discharge or advisory reported
  • Incomplete source coverage
Limited records

3 discharge reports have no end time and are not marked ongoing; under DirtyWaterWatch rules they show caution, not a discharge or advisory status, and add no hours here.

Source: ny-dec-sprtk. Records cover August 11, 2021 to November 2, 2026.

Show table

Share of the May to October season with a discharge or advisory status

Share of the hours from May 1 to October 31 with a discharge or advisory status under DirtyWaterWatch rules.

  • Discharge or advisory reported
  • Season with incomplete source coverage

Seasons with incomplete source coverage: 2021. The share is of the hours a source covered. 3 discharge reports have no end time and are not marked ongoing; under DirtyWaterWatch rules they show caution, not a discharge or advisory status, and add no hours here.

Source: ny-dec-sprtk. Records cover August 11, 2021 to November 2, 2026.

Show table

Reported discharges by calendar month, all years

Every counted discharge report, by the calendar month it began.

Months are summed over every year a tracked source covers; the table gives the number of years behind each month.

Source: ny-dec-sprtk. Records cover August 11, 2021 to November 2, 2026.

Show table

Reported discharges by wastewater outlet

Wastewater outlets with the most tracked discharge records: 2 of 2, all years. Counts depend on reporting coverage and do not measure legal compliance or harm.

Source: ny-dec-sprtk. Records cover August 11, 2021 to November 2, 2026.

Show table
How these charts are counted

We count each discharge once. Where a source publishes notices and confirmed reports, we use confirmed reports for an operator's month when available; otherwise we use notices. We combine revisions and exclude duplicate state reports copied by the U.S. Environmental Protection Agency (EPA). Monthly and yearly totals appear separately. Status hours follow this site's rules. Shaded gaps mean missing coverage, not zero discharges.

  • ny-dec-sprtk: records from August 11, 2021 to the latest update

Reports linked to Tappan Zee

Reports linked to Tappan Zee, newest first
StartEnd Sewer operator OutletTypeVolumeSourceLinks
Aug 20, 2026, 9:45 PM EDT Aug 20, 2026, 10:22 PM EDT Orangetown (T) SD #2 STP Parking lot outside of pump station Report not fully read “10 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2695626164914304, reported Aug 25, 2026, 1:00 PM EDT, retrieved 2026-11-02 20:40 UTC · Read the original notice
Aug 20, 2026, 9:45 PM EDT ongoing (as reported) Orangetown (T) SD #2 STP Parking lot outside of pump station Report not fully readEarlier version “10 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2691743514384965, reported Aug 20, 2026, 10:18 PM EDT, retrieved 2026-11-02 20:40 UTC · Read the original notice
Aug 3, 2026, 5:32 AM EDT Aug 3, 2026, 6:35 AM EDT Orangetown (T) SD #2 STP Not provided Report not fully read “275 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2666454747004304, reported Aug 7, 2026, 7:04 PM EDT, retrieved 2026-11-02 20:40 UTC · Read the original notice
Aug 3, 2026, 5:32 AM EDT ongoing (as reported) Orangetown (T) SD #2 STP Not provided Report not fully readEarlier version “275 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2652126736141754, reported Aug 3, 2026, 5:42 AM EDT, retrieved 2026-11-02 20:40 UTC · Read the original notice
Jul 29, 2026, 1:50 AM EDT ongoing (as reported) Orangetown (T) SD #2 STP Not provided Report not fully read “275 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2637661286186955, reported Jul 29, 2026, 3:24 AM EDT, retrieved 2026-11-02 20:40 UTC · Read the original notice
Jul 21, 2026, 11:50 AM EDT Jul 21, 2026, 12:27 PM EDT Orangetown (T) SD #2 STP Not provided Report not fully read “275 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2625772816933702, reported Jul 21, 2026, 12:55 PM EDT, retrieved 2026-11-02 20:40 UTC · Read the original notice
Mar 6, 2026, 12:11 AM EST ongoing (as reported) Orangetown (T) SD #2 STP Last manhole before pump station Sanitary sewer overflow (SSO) “100 Gallons per Minute Estimated” Orangetown (T) SD #2 STP (NY DEC Sewage Pollution Right to Know), record 2384807971594142, reported Mar 6, 2026, 12:25 AM EST, retrieved 2026-11-02 20:40 UTC · Read the original notice

All reports in New York by year: 2026 (7 here)

Wastewater outlets on this water

Outfall: a pipe or outlet where wastewater enters a water body.

No wastewater outlet in our records is linked to this water.

Boat launches

Source: OpenBoatLaunch launch records (public agency data and OpenStreetMap, Open Database License). · Tappan Zee on OpenBoatLaunch

Marinas and clubs on this water

Marina or club: not public access.

Nearby waters

Sources covering this water

7 records linked to this water. Updated .