Wapato Lake might be contaminated with sewage from the Tacoma Mall.
One of the mall’s sewer lines is improperly linked to a pipe that carries storm runoff to a marsh feeding the South End lake, a neighborhood treasure.
Tacoma public works inspectors discovered the problem Wednesday, city officials said.
About half of the mall’s wastewater – including from the food court area – has been flushed into a stormwater line that ends just north of the lake, said James Parvey, a Public Works Department manager.
Mall manager Steve Heim said workers corrected the mistake on Friday.
“It’s a fix that solves the problem. There’ll be a permanent solution on Monday,” he said Friday afternoon. “We found out about it Thursday and took care of it today.”
The park surrounding Wapato Lake has been a gathering place for generations of Tacomans. But the 30-acre lake is plagued by pollution problems that have killed fish, birds and wildlife. Things got so bad that Metro Parks last year hired a consultant to devise a solution, most likely chemical treatment.
Wednesday’s finding of the faulty sewer connection was unrelated to the Metro Parks effort, but parks officials said they hope the fix will benefit water quality.
“It’s great that the city’s testing has led to this discovery,” said parks spokeswoman Nancy Johnson.
Public Works Department inspectors identified the problem during routine smoke testing of the lines.
A dye test Thursday morning confirmed that water from toilets was flushed into the stormwater system instead of the city’s sewers. City officials met with mall managers Friday morning, Parvey said.
“There’s a cross-connection somewhere,” he said. “We’re putting in a temporary pump system to separate (the lines) again.”
There is no immediate threat to public health, said Ray Hanowell, an environmental health specialist for the Tacoma-Pierce County Health Department, which tests lake water. But health officials will know more early next week after a laboratory analyzes fresh samples for bacteria.
One reason Hanowell said health officials aren’t worried is that the drain is dry at its endpoint, north of the lake.
The pipe has been empty for about 11/2 months, which suggests leaks between the mall and the marsh, he said.
At this point, no one knows how much or how long sewage from the mall has been fed into the city’s storm drains. The city last inspected the mall’s system in 1992 and found no problems, officials said.
Both city and mall officials plan to investigate further.
“It could be as simple as a single tenant,” said Heim, the mall manager. “The research has to be done.”
The state Department of Ecology also is looking into the matter, but spokeswoman Shannon Sullivan said it’s too early to say whether a penalty will be issued.
“Our immediate concern is how they are going to stop the flow,” she said Friday morning.
The Simon Property Group, which manages the mall, sent out a news release saying managers are cooperating with city officials.
“Our primary concern is always for the safety of our shoppers and mall employees. We pride ourselves on being a good community partner and neighbor,” the company said.
Parvey said the city performs smoke tests primarily because of concerns about excess water in the sewer lines, which can overwhelm the treatment plan after storms.
Construction workers sometimes make improper connections, such as tying downspouts into the sewers, he said.
“It seems to be a recurring problem,” he said.
The last time inspectors undertook this kind of sewer and storm-drain inspection program was more than 10 years ago. Testing all the lines takes more than a year, officials said.
Susan Gordon: 253-597-8756
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