The San Lorenzo River is cleaner than many may think, but continues to exceed state standards for acceptable levels of harmful bacteria in the water. Certain types of harmful bacteria like E. coli or Enterococcus can make people and animals sick. Harmful bacteria can come from humans, pets or from our day-to-day lives. Until human-caused sources of bacteria in the river are zero, there is still work to do to improve water quality.

As rainwater flows over land surfaces into the San Lorenzo River, it picks up potential pollutants, including bacteria from human and animal waste. Reducing the amount of human and human-caused bacteria that enters the river is key to making the San Lorenzo River a swimmable and fishable river, and improving health of the entire watershed.

We can all do our part to stop bacteria pollution affecting the San Lorenzo River.


On May 24, the Coastal Watershed Council, in partnership with the City of Santa Cruz launched a public information campaign to engage Santa Cruz residents and business owners in reducing common bacterial pollutant entering the San Lorenzo River. Here are three common human sources affecting the San Lorenzo River.

  1. Dry season, human caused flows into storm drains
  2. Leaking sewer lateral pipes that connect your home to the sewer main
  3. Pet waste left behind in backyards and public space

You can learn more about human-caused or incidental flows and pet waste and what you can do to protect the San Lorenzo River here.