Sejal Choksi-Chugh is the Executive Director of San Francisco Baykeeper, an environmental group that tracks pollution threats.
"So it can include pathogens, bacteria, viruses that can get into the water. And if someone comes into contact with that water, it can have a harmful effect on their health," Choksi-Chugh argues.
VIDEO: Here's before-and-after look at hardest-hit areas in Capitola, Santa Cruz
Before-and-after look at hardest-hit areas on Santa Cruz Co. coastline
They say the episode is an extreme example of a challenge that's been building for decades. Recent estimates place the cost of upgrading the dozens of wastewater systems that ring the Bay in the billions of dollars. But groups like Baykeeper say the upgrades are critical to protecting the Bay, calling for increased federal spending during President Biden's recent visit to the Bay Area to assess the storm damage.
"And when those sewer pipes get overwhelmed, then you just have too much water in the system in the wastewater system. And you know, they're not equipped to handle this, this much water. And that's why we're really pushing for upgrades at all levels," says Choksi-Chugh.
Experts say there are added pressures from climate-driven factors as well, including fluctuating cycles of intense storms. Recent studies also point to sea level rise, pushing heavier saltwater underneath the Bay shoreline, potentially raising the water table and further degrading underground pipes, especially during heavy storm cycles.
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Eileen White is the Executive Officer of the San Francisco Bay Regional Water Quality control board.
"So what we saw on Dec. 31, and then the first couple of weeks in January, we can expect to become the new normal with climate change," White believes.
She echoes the need for state and federal funding but points out that many of the major wastewater districts in the Bay Area are already spending on upgrades.
"There's a lot of good work going on in the Bay Area, to look at climate change and what needs to be done to prepare these wastewater systems so that they're more resilient in the future. And for example, San Francisco issued have worked with the regional board a year ago. And they entered an agreement with us where they're going to spend over $600 million between now and 2028, to make improvements," White says.
Last year's destructive algae bloom on San Francisco Bay also put a spotlight on potential upgrades to the area's wastewater treatment system. That's because nutrients contained in the treated wastewater could be a driver for the algae growth.