In the late 1990s and early 2000s, the City of San Diego had a major increase in sewage spills. In fact, in 2000 alone there were 365 sewer spills, an average of one per day. This increase in spills was due in large part because the City's aging sewer infrastructure was in need of replacement, repair and upgrades. Some pipelines had been in operation for a hundred years.

Beginning in 2007, the City's sewer rates were increased to operate, maintain, repair and upgrade the City's wastewater system. The rate increases are paying for more than $585 million of necessary sewer system upgrades. These projects include replacement of sewer mains, sewer pipeline rehabilitation and sewer pump station improvements.

The Public Utilities Department keeps track of the number of sewage spills that occur in the City, and these system improvements as well as increased sewer line cleaning have made a big difference. After the high of 365 spills in 2000, there were 41 in 2010, and 36 in 2020. The Public Utilities Department continues to improve the City's sewer system through upgrades and inspections to keep sewer spills to a minimum.

The statistics below show the dramatic decrease in spills over the years.

• Sewer Spills by Year 2000 - 2023
• Sewer Spills by Cause 2003 - 2023
• Sewer Spills Graph 2000 - 2023
• Sewer Spills by Month in 2023
• Sewer Spills - Comparing 2022 with 2023