Lake Welch
Reservoir in New York, near Thiells
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
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.
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: State Park beaches (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 .
The last 90 days
No discharge, advisory or caution periods are shown for this water in this time span. Check downstream stretches and source coverage.
Source: DirtyWaterWatch calculations using the reports named above and the published status rules. Updated 2026-11-02 21:26 UTC.
Reported discharges over time
- Hours with a discharge or advisory status on the Lake Welch in New York, last 12 months0Reported on the Lake Welch in New York: 0 · 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.
- 2025 season with a discharge or advisory status on the Lake Welch in New York1.6%May to October 2025; incomplete source coverageShare 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 Lake Welch in New York0Reported on the Lake Welch in New York: 0 · 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.
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
- No tracked source for this period
- Incomplete source coverage
No tracked source covers October 2025 to November 2026. 3 discharges reported to last more than 31 days are counted as 31 days.
Source: ny-parks-beaches. Records cover May 19, 2015 to September 2, 2025.
Show table
| Month | Hours with a discharge or advisory status | Hours from post-discharge periods | Hours from official advisories only | Hours in the month | Coverage |
|---|---|---|---|---|---|
| January 2022 | 0 | 0 | 0 | 744 | |
| February 2022 | 0 | 0 | 0 | 672 | |
| March 2022 | 0 | 0 | 0 | 744 | |
| April 2022 | 0 | 0 | 0 | 720 | |
| May 2022 | 0 | 0 | 0 | 744 | |
| June 2022 | 120 | 0 | 120 | 720 | |
| July 2022 | 648 | 0 | 648 | 744 | |
| August 2022 | 0 | 0 | 0 | 744 | |
| September 2022 | 0 | 0 | 0 | 720 | |
| October 2022 | 0 | 0 | 0 | 744 | |
| November 2022 | 0 | 0 | 0 | 720 | |
| December 2022 | 0 | 0 | 0 | 744 | |
| January 2023 | 0 | 0 | 0 | 744 | |
| February 2023 | 0 | 0 | 0 | 672 | |
| March 2023 | 0 | 0 | 0 | 744 | |
| April 2023 | 0 | 0 | 0 | 720 | |
| May 2023 | 0 | 0 | 0 | 744 | |
| June 2023 | 240 | 0 | 240 | 720 | |
| July 2023 | 72 | 0 | 72 | 744 | |
| August 2023 | 0 | 0 | 0 | 744 | |
| September 2023 | 0 | 0 | 0 | 720 | |
| October 2023 | 0 | 0 | 0 | 744 | |
| November 2023 | 0 | 0 | 0 | 720 | |
| December 2023 | 0 | 0 | 0 | 744 | |
| January 2024 | 0 | 0 | 0 | 744 | |
| February 2024 | 0 | 0 | 0 | 696 | |
| March 2024 | 0 | 0 | 0 | 744 | |
| April 2024 | 0 | 0 | 0 | 720 | |
| May 2024 | 0 | 0 | 0 | 744 | |
| June 2024 | 0 | 0 | 0 | 720 | |
| July 2024 | 168 | 0 | 168 | 744 | |
| August 2024 | 0 | 0 | 0 | 744 | |
| September 2024 | 0 | 0 | 0 | 720 | |
| October 2024 | 0 | 0 | 0 | 744 | |
| November 2024 | 0 | 0 | 0 | 720 | |
| December 2024 | 0 | 0 | 0 | 744 | |
| January 2025 | 0 | 0 | 0 | 744 | |
| February 2025 | 0 | 0 | 0 | 672 | |
| March 2025 | 0 | 0 | 0 | 744 | |
| April 2025 | 0 | 0 | 0 | 720 | |
| May 2025 | 0 | 0 | 0 | 744 | |
| June 2025 | 0 | 0 | 0 | 720 | |
| July 2025 | 48 | 0 | 48 | 744 | |
| August 2025 | 0 | 0 | 0 | 744 | |
| September 2025 | 0 | 0 | 0 | 720 | Incomplete source coverage |
| October 2025 | 0 | 0 | 0 | 744 | No tracked source for this period |
| November 2025 | 0 | 0 | 0 | 720 | No tracked source for this period |
| December 2025 | 0 | 0 | 0 | 744 | No tracked source for this period |
| January 2026 | 0 | 0 | 0 | 744 | No tracked source for this period |
| February 2026 | 0 | 0 | 0 | 672 | No tracked source for this period |
| March 2026 | 0 | 0 | 0 | 744 | No tracked source for this period |
| April 2026 | 0 | 0 | 0 | 720 | No tracked source for this period |
| May 2026 | 0 | 0 | 0 | 744 | No tracked source for this period |
| June 2026 | 0 | 0 | 0 | 720 | No tracked source for this period |
| July 2026 | 0 | 0 | 0 | 744 | No tracked source for this period |
| August 2026 | 0 | 0 | 0 | 744 | No tracked source for this period |
| September 2026 | 0 | 0 | 0 | 720 | No tracked source for this period |
| October 2026 | 0 | 0 | 0 | 744 | No tracked source for this period |
| November 2026 | 0 | 0 | 0 | 42 | No tracked source for this period |
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
- No tracked source for this period
- Incomplete source coverage
No tracked source covers 2026. 3 discharges reported to last more than 31 days are counted as 31 days.
Source: ny-parks-beaches. Records cover May 19, 2015 to September 2, 2025.
Show table
| Year | Hours with a discharge or advisory status | Share of the year | Coverage |
|---|---|---|---|
| 2015 | 96 | 1.1% | Incomplete source coverage |
| 2016 | 144 | 1.6% | |
| 2017 | 48 | 0.5% | |
| 2018 | 0 | 0.0% | |
| 2019 | 72 | 0.8% | |
| 2020 | 96 | 1.1% | |
| 2021 | 336 | 3.8% | |
| 2022 | 768 | 8.8% | |
| 2023 | 312 | 3.6% | |
| 2024 | 168 | 1.9% | |
| 2025 | 48 | 0.5% | Incomplete source coverage |
| 2026 | 0 | 0.0% | No tracked source for this period |
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-parks-beaches: records from May 19, 2015 to September 2, 2025
Reports linked to Lake Welch
| Start | End | Sewer operator | Outlet | Type | Volume | Source | Links |
|---|---|---|---|---|---|---|---|
| Jul 15, 2025 | Jul 16, 2025 | not stated | Harriman SP: Lake Welch (Chair 0) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2025-07-15, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 15, 2025 | Jul 16, 2025 | not stated | Harriman SP: Lake Welch (Chair 08) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2025-07-15, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 9, 2024 | Jul 15, 2024 | not stated | Harriman SP: Lake Welch (Chair 0) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2024-07-09, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 9, 2024 | Jul 15, 2024 | not stated | Harriman SP: Lake Welch (Chair 08) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2024-07-09, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 9, 2024 | Jul 15, 2024 | not stated | Harriman SP: Lake Welch (Chair 17) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2024-07-09, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 5, 2023 | Jul 6, 2023 | not stated | Harriman SP: Lake Welch (Chair 0) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2023-07-05, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 5, 2023 | Jul 7, 2023 | not stated | Harriman SP: Lake Welch (Chair 08) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2023-07-05, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 20, 2023 | Jun 24, 2023 | not stated | Harriman SP: Lake Welch (Chair 0) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2023-06-20, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 20, 2023 | Jun 24, 2023 | not stated | Harriman SP: Lake Welch (Chair 08) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2023-06-20, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 20, 2023 | Jun 24, 2023 | not stated | Harriman SP: Lake Welch (Chair 17) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2023-06-20, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 11, 2023 | Jun 15, 2023 | not stated | Harriman SP: Lake Welch (Chair 0) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2023-06-11, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 26, 2022 | Sep 6, 2022 | not stated | Harriman SP: Lake Welch (Chair 0) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2022-06-26, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 26, 2022 | Sep 6, 2022 | not stated | Harriman SP: Lake Welch (Chair 08) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2022-06-26, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 26, 2022 | Sep 6, 2022 | not stated | Harriman SP: Lake Welch (Chair 17) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2022-06-26, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 6, 2021 | Jul 7, 2021 | not stated | Harriman SP: Lake Welch (Chair 17) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2021-07-06, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 22, 2021 | Jun 23, 2021 | not stated | Harriman SP: Lake Welch (Chair 17) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2021-06-22, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 1, 2021 | Jun 10, 2021 | not stated | Harriman SP: Lake Welch (Chair 0) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2021-06-01, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 1, 2021 | Jun 4, 2021 | not stated | Harriman SP: Lake Welch (Chair 08) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2021-06-01, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jun 1, 2021 | Jun 10, 2021 | not stated | Harriman SP: Lake Welch (Chair 17) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2021-06-01, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 25, 2020 | Jul 28, 2020 | not stated | Harriman SP: Lake Welch (Chair 08) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2020-07-25, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Aug 18, 2019 | Aug 20, 2019 | not stated | Harriman SP: Lake Welch (Chair 17) | Cyanobacteria advisory (harmful blue-green algae) | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2019-08-18, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 5, 2017 | Jul 6, 2017 | not stated | Harriman SP: Lake Welch (Chair 0) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2017-07-05, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 5, 2017 | Jul 6, 2017 | not stated | Harriman SP: Lake Welch (Chair 08) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-08:lake-welch:2017-07-05, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Sep 13, 2016 | Sep 14, 2016 | not stated | Harriman SP: Lake Welch (Chair 0) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-0:lake-welch:2016-09-13, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
| Jul 19, 2016 | Jul 20, 2016 | not stated | Harriman SP: Lake Welch (Chair 17) | Beach closure | volume not reported | NYS Office of Parks, Recreation and Historic Preservation (State Park beaches), record harriman-sp-lake-welch-chair-17:lake-welch:2016-07-19, the source gives no report time, retrieved 2026-11-02 21:19 UTC · Read the original notice | Open record below · Map |
Read the full record | |||||||
Showing the latest 25 records of 29 records. See them all with filters.
All reports in New York by year: 2025 (2 here) · 2024 (3 here) · 2023 (6 here) · 2022 (3 here) · 2021 (5 here) · 2020 (1 here) · 2019 (1 here) · 2017 (2 here) · 2016 (3 here) · 2015 (3 here)
Beaches named in these records: Harriman SP: Lake Welch (Chair 0), Harriman SP: Lake Welch (Chair 08), Harriman SP: Lake Welch (Chair 17).
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
- Lake Welch Boat Launch, Thiells · Boat ramp
Source: OpenBoatLaunch launch records (public agency data and OpenStreetMap, Open Database License). · Lake Welch on OpenBoatLaunch
Nearby waters
- Lake Tiorati, NY No current status shown about 4 km away
- Lake Sebago, NY No current status shown about 5 km away
- Cedar Pond Brook, NY No current status shown about 6 km away
- Tappan Zee, NY No current status shown about 20 km away
- Ramapo River, NJ No current status shown about 22 km away
Sources covering this water
- State Park beaches · Latest check succeeded · Last successful check: 2026-11-02 21:20 UTC
29 records linked to this water. Updated .