A test of water at Tempe Town Lake on Wednesday, April 25, revealed that the man-made urban lake had a pH level that exceeded the standard for swimming. As a result, the city’s Splash & Dash event has been canceled. The full statement by the city reads as follows:
“The City of Tempe has issued a statement regarding the water quality of Tempe Town Lake. cares about the health of Tempe Town Lake users and is committed to ensuring the water quality of the lake meets or exceeds all county standards. During routine testing, elevated pH levels were detected in the lake. The city’s water quality experts began treating the lake to bring the levels down to a pH of 9.0 or less, which is the Full Body Contact standard for swimming. As of this morning’s test, the lake had a pH of 9.2, which exceeds the standard. Some swimmers could experience irritated skin if they swim in a body of water with elevated pH.
“As a result, the organizers of tomorrow’s Splash & Dash event have decided to cancel. The city will continue to treat the lake until it returns to a pH of 9.0 or less. In anticipation of Sunday’s Cactus Man triathlon, treatments are planned for tomorrow and Friday. No other activities or classes occurring at Tempe Town Lake are impacted. The city will provide updates about the lake pH as treatments continue.
“Tempe Town Lake is a living ecosystem that has changed significantly over the past two decades. This past winter, waterways across the state experienced excessive golden algae blooms, which resulted in significant fish die offs. Golden algae effects organisms that breathe with gills. This phenomenon, along with weather and other changes to the lake’s ecosystem, all play a role in increased algae and, therefore, increased pH. The city conducts routine tests to ensure that the lake’s water meets or exceeds all regulatory guidelines.”