The city of Los Angeles accepted legal responsibility yesterday for a decade’s worth of sewage spills, numbering 3,668 in all. The spills polluted streets and water bodies, in violation of both state and federal clean-water laws. After a four-year legal battle with government officials, environmental organizations, and community members, the city has finally owned up to all the overflows in an effort, it says, to prove its good-faith intentions to improve its antiquated sewers. It also hopes that coming clean will discourage the courts from levying expensive fees for the thousands of clean-water violations. L.A. has promised to reduce the number of spills 25 percent by 2005, but critics note that even with the improvements, the city would still experience hundreds of sewage leaks per year.