Poppies

Water Quality Stop Light Designations

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Program Overview

The East Bay Regional Park District uses a three-color stop light to indicate water quality safety. Bacteria testing is preformed weekly April through October and twice monthly November through March. 

Green Light - Low Health Risk

Beach is open. Bacteria tests are within state health standards.

Yellow Light - Increased Health Risk

Beach is open. Bacteria tests are NOT within state health standards.

Red Light - Hazardous to Human Health

Beach is CLOSED. Bacteria are hazardous to human health. NO SWIMMING.

Stop Light Signage

Green Light: bacteria standards meet state standards. Swimming is open.
Yellow Light: Bacteria standards do not meet state health advisory thresholds. Swimming remains open.
Red Light: bacteria present a hazard to human health. NO SWIMMING.

Please be advised there is always some level of risk when swimming in any water body. To have a fun and safe experience swimming in the parks, we encourage you to follow a few simple rules:

  • Keep water out of your mouth
  • After you leave the water, shower and towel dry as soon as possible
  • Do not swim in the lake for 3 days after a rainstorm
  • Check posted signs for water quality information

For more information contact the East Bay Regional Park District Water Management Department at (510) 544-2328

For recent postings at Park District waterbodies, check our Current Water Quality Conditions page.

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