A sewage spill that closed part of east Mission Bay in San Diego earlier this year could cost the City millions of dollars in fines, NBC 7 learned Monday.

In January, a landslide in Tecolote Canyon broke a main sewer line, dumping more than 100,000 gallons of raw sewage into the Tecolote Creek and east Mission Bay.

On Monday, the San Diego Regional Water Quality Control Board verified the sewage spill actually dumped more than 6.7 million gallons of untreated sewage into Tecolote Creek, which later leaked into East Mission Bay.

A sewage spill has prompted water closures in Mission Bay ahead of Memorial Day Weekend. NBC 7’s Wendy Fry reports.

"That's disgusting. That is straight up disgusting,” Mission Bay visitor Zuri Walker said.

Walker told NBC 7 that Mission Bay is her favorite place to run, but the water is something she appreciates from a distance.

“The only time I go in [there] is when I go wake-boarding around the other side and even then, it's not that great,” Walker said.

Other Mission Bay visitors had a similar reaction.

"It's a shame we are one of the richest countries in the world we can't even put our garbage away," kite surfer, Marko Bartscherer said.

The new figure was revealed in a technical report completed by the City and issued to the San Diego Regional Water Quality Control Board.

“We would say that is a sizable spill,” Water Control Board Supervising Engineer David Barker said.

Barker says the City promptly responded to the spill, fixed the broke sewer line in about a day and warned the community. Crews also recovered 108,000 gallons of sewage.

But he added that the Water Control Board is also investigating whether there was any "negligence" by the City of San Diego in following proper procedures for the spill.

If so, the City might have to pay $10 per gallon or a maximum of $65 million.

In 2001, San Diego had paid more than $1.5 million in fines for a spill in Tecolote Creek, according to the water control board.

This investigation could take up to two years to complete.

NBC 7 reached out to the City of San Diego for a response. Before noon Tuesday, we received this statement:

"In January 2016 a major rain storm caused a minor localized landslide in Tecolote Canyon that took a section of sewer pipe with it. The City followed all reporting requirements for this sewage spill, including notifying the public of the subsequent beach closures along sections of Mission Bay. The City is working with the Regional Water Quality Control Board to provide all requested information about the spill and the City's response to the emergency. We believe this event was an unprecedented natural event and the City's response was appropriate."