Most CalPERS benefit plans are currently between 65 and 80 percent funded.
Board members say the accounting changes will fully-fund the system within 30 years. But the burden will fall on local governments.
"I think for some cities it could be quite difficult," says Natasha Karl with the League of California Cities.
She says the changes could mean a 30 to 50-percent increase in contributions for cities over 10 years beginning in 2015.