We don’t, or at least not by the sewer design. Sure, hurricanes and tornadoes can and have destroyed treatment facilities, but that’s not the same thing as intentionally designing for any amount of sewage to enter the waterways.
The US is a massive country friend, there are lots of places with combined sewers (domestic wastewater and stormwater) that will bypass treatment when there is a big rain event, especially in coastal cities that discharge wastewater to the ocean. It’s not ideal but the alternative is massively oversized treatment plants or replacing all of the existing sewer infrastructure to separate the sewers. Both options would cost tens of billions of dollars in any of the large east coast cities. People are not willing to pay for that.
We don’t, or at least not by the sewer design. Sure, hurricanes and tornadoes can and have destroyed treatment facilities, but that’s not the same thing as intentionally designing for any amount of sewage to enter the waterways.
You’re just not paying attention. Here is the EPA map of where Combined Sewer Outflows happen.
As you can see, it’s hundreds of American communities, including major cities like New York, Chicago, DC, San Francisco, Seattle.
The US is a massive country friend, there are lots of places with combined sewers (domestic wastewater and stormwater) that will bypass treatment when there is a big rain event, especially in coastal cities that discharge wastewater to the ocean. It’s not ideal but the alternative is massively oversized treatment plants or replacing all of the existing sewer infrastructure to separate the sewers. Both options would cost tens of billions of dollars in any of the large east coast cities. People are not willing to pay for that.