TMZ broke the story ... Steve died Monday as a result of liver failure. He had been in hospice and over the weekend he was only given days to live, receiving end-of-life care at home.
Despite Steve's death, it's still business as usual for Smash Mouth ... we're told the band will continue to tour with new singer Zach Goode. The band's not planning to cancel any gigs unless Steve's memorial takes place during a previously scheduled event.
With Smash Mouth's frontman gone, the band's manager says ... "Steve's legacy will live on through the music."