data . willkara
dataset · Chicago Park District via Chicago Data Portal

Chicago beach water-quality automated sensors

Hourly Lake Michigan telemetry from Park District buoys at six Chicago beaches: water temperature, wave height, wave period, and turbidity. Sensor coverage has narrowed over time — only Ohio Street Beach is actively reporting in 2026.

data through 2026-06-13 · 46,676 sensor rows

About this dataset

Chicago Park District's lakefront automated sensors, mirrored on the Chicago Data Portal as Socrata dataset qmqz-2xku. Each row is one hourly reading from one in-water buoy: water temperature (°C), wave height (m), wave period (s), turbidity (NTU), transducer depth (m), and a battery-life voltage that signals when the sensor needs service.

Source

  • Catalog page: Chicago Data Portal
  • Endpoint (SODA v3): POST https://data.cityofchicago.org/api/v3/views/qmqz-2xku/query.json
  • Companion sensor-locations dataset (lat/lon per sensor): g3ip-u8rb
  • Rows: 46,676 (one per sensor per hour while in operation)

The shrinking network

Six water sensors operated at the 2014–2015 peak (63rd Street, Calumet, Montrose, Ohio Street, Osterman, Rainbow). By 2019 only Ohio Street Beach was reporting. A brief multi-beach return in 2025 ended in mid-March — most beaches' last reading is dated 2025-03-18. As of 2026 only Ohio Street Beach is still publishing hourly readings.

Any story comparing beaches needs to pick a season when more than one was online. The companion editorial piece The swimmer's safety gauge uses summer 2015 (May 1 – October 1) — the last full-season multi-sensor record.

Caveats

  • Turbidity is a proxy, not a pathogen count. Cloudiness in NTU correlates with biological contamination but doesn't measure it directly. Chicago's official beach advisory is driven by a separate 24-hour-lab E. coli result, not by these sensor readings.
  • Sensor coverage has battery-failure gaps. The battery_life voltage field exists precisely to flag impending dropouts; periods where it falls below operational thresholds are sometimes followed by weeks of silence.
  • Beach names drift. "Ohio Street Beach Buoy" and "Ohio Street Beach" appear as separate beach_name values in the historical record — the buoy was renamed at some point. "New Site" and "Old - Ohio Street Beach" are similar artifacts. Filter to the canonical names when joining.

Citation

Chicago Park District (2026). Beach Water Quality — Automated Sensors. Retrieved 2026-06-13 via Chicago Data Portal SODA v3.