(KERO) — Later this week anyone wanting to drink inside most San Francisco bars will need to show proof of vaccination or a negative COVID-19 test.

The San Francisco Bar Owner Alliance, which represents more than 500 bars in the city, said in a statement "we are obligated to protect our workers and their families and to offer safe space for customers to relax and socialize."

Proof of a negative test or vaccination will not be required for customers who sit outside. The measure takes effect Thursday.

Each bar will need to determine its own way to enforce the rule.