About 50,000 gallons of partially-treated sewage overflowed Wednesday from a water treatment plant in south St. Petersburg.
Officials say heavy rains caused the spill at the city's southwest plant on 54th Avenue South around 9 p.m. The spill was contained to the plant's property, with most of it flowing into a stormwater retention pond.
Construction at the wastewater plant caused decreased capacity in a basin that adds chlorine to the treated sewage.
Mayor Rick Kriseman says the city is working with the construction company to better plan for times when parts of the plant have to be shut down.
"In instances where things are going to have to be taken offline, to make sure that we are keeping a good eye on the weather forecasts so that we try and minimize events like yesterdays," Kriseman said.
Since the spill happened during the final step in the process, officials say the water was mostly treated.
The city reported the spill Thursday morning.
Multiple spills over the past two years forced the city to upgrade its water treatment facilities and construction at the southwest plant will double its capacity.