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California / Waters /

Mad River

River in California, past McKinleyville

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.

Ringed dots mark treatment plant outfalls. Square boat markers mark boat launches listed by OpenBoatLaunch. Larger round markers with a label mark beach and other official advisories nearby.

Check McKinleyville Community Service District's notices · Bookmark this water page and check it before each trip · Report a missing notice or error

About this status

No current status shown: no report we track sets a status on this water now; how statuses work. No status does not mean the water is safe. Follow posted signs and local health advice.

Sources checked: State Water Board CIWQS Sanitary Sewer System spill data: Cat1-2-3-Spills.txt (nightly flat file) (last successful check 2026-11-06 08:37 UTC); Surface Water - Freshwater Harmful Algal Blooms (last successful check 2026-11-06 08:37 UTC); a public source (last successful check 2026-11-06 08:38 UTC); a public source (last successful check 2026-11-06 08:39 UTC). Status by DirtyWaterWatch, updated 2026-11-06 09:03 UTC. · Updated

The last 90 days

Last 90 days, hour by hour. Red: discharge or advisory reported. Amber: caution. Hatched amber: end not confirmed. Plum: algal bloom advisory. Red or amber with a light line inside: beach advisory or caution. Dotted: monthly report (days with discharge, dates not given). Grey: no current status on the water outline. Purple hatching: a status resting on a source that could not be checked on schedule.

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 2026-11-06 09:03 UTC.

Reported discharges over time

  • Discharges affecting the Mad River in California, last 12 months0December 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once. Arriving discharges are estimated from modeled downstream reaches.
  • Records behind the last-90-days strip for the Mad River in California0last 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.

This record covers the Mad River within California; the same river upstream is a separate record.

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.

Reported discharges per month

0 reported discharges, January 2022 to November 2026.

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

Sources: ca-swrcb-ciwqs-spills-flatfile; U.S. Environmental Protection Agency sewer overflow records. Records cover January 1, 2022 to November 6, 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.

  • ca-swrcb-ciwqs-spills-flatfile: records from January 1, 2022 to the latest update
  • U.S. Environmental Protection Agency sewer overflow records: records from May 3, 2022 to the latest update (limited records)

Reports linked to Mad River

Cyanobacteria (harmful blue-green algae) can make water unfit for contact; the issuing authority decides when its advisory ends.

Reports linked to Mad River, newest first
WhenReportStatus
California State Water Resources Control Board (FHAB program) · Mad River at Pump Station 4 · Algae advisory · volume not reported report · notice · maplisted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · at County Boat Ramp · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near Hatchery Road Bridge · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · Arcata · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near Blue Lake · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near intersection of Mad River/Hwy 504 · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near Rush-Zenia Rd · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near Tule Divide Rd · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near Lost Bridge Rd · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’21California State Water Resources Control Board (FHAB program) · near Mad River Rd Bridge · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’20California State Water Resources Control Board (FHAB program) · Mad River at Blue Lake · Algae advisory · volume not reported report · notice · maplifted
to Dec 31 ’18California State Water Resources Control Board (FHAB program) · Mad River at Blue Lake Bridge · Algae advisory · volume not reported report · notice · maplifted

Sources: Surface Water - Freshwater Harmful Algal Blooms, retrieved 2026-11-06 03:07 UTC. A report's record id and times show when you hover or focus its "report" link.

Download these reports as CSV

All reports in California by year: 2026 (1 here) · 2021 (9 here) · 2020 (1 here) · 2018 (1 here)

Wastewater outlets on this water

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

Treatment plant outfalls

1 outfall

Source: U.S. Environmental Protection Agency (EPA) permit records (ICIS-NPDES permitted features): where a treatment plant’s permitted discharge leaves. No national source says whether a plant outfall is open or closed.

Sewer operators listed for this water: McKinleyville Community Service District.

Boat launches

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

Nearby waters

Sources covering this water

12 records linked to this water. Updated .