Green-colored water appeared in Warsaw’s Służewiczek Stream yesterday and today, sparking alarm among residents after officials confirmed the hue was a test dye from the city’s heating network.
Why the water turned green?
The bright green water in Warsaw’s Służewiczek Stream, seen yesterday and today along Dolina Służewiecka and most prominently below the beaver dam at Anoda, is not pollution but the result of a leak‑testing operation on the city’s heating network. Officials and Veolia confirmed the colour came from a fluorescent dye injected into the system during surveillance work, easing residents’ concerns that the water was environmentally contaminated.
Veolia explains the dye
According to Veolia’s technical manager Paweł Zbiegniewski, the dye used is fluorescein, a green pigment specifically chosen to detect leaks in the heating network. He noted that if the network were to rupture, the dye would be released into the surrounding environment, the vivid colour allowing operators to pinpoint the leak site promptly.
Safety and environmental impact of fluorescein
Fluorescein is a standard technological dye used worldwide in district‑heating systems for leak detection. Small amounts are sufficient for visibility without harming humans or wildlife.
The dye is biodegradable, behaving like a food colouring; it gradually degrades over a few days, after which the stream’s colour should return to normal.
Monitoring techniques beyond dye
Veolia reminded that dyeing is just one element of continuous infrastructure monitoring. The company also employs thermographic cameras; in February a drone captured thermal images over half of Warsaw, identifying around 100 potential heat‑loss points in the heating network. The remaining areas await suitable weather conditions for further scans.
Connection to recent heating network failure
The latest appearance of fluorescein in the Służewiczek Stream likely relates to a recent heating‑network breakdown on Ursynów’s Witolda Zawadowskiego Street, where a network leak was reported.
