San Diego County water officials have long been at odds with their counterparts in Los Angeles, who control millions of gallons imported every day into the southwest corner of California. But a new dispute has broken out between the Metropolitan Water District of Southern California and its member agency, the San Diego County Water Authority — and it’s not about the wet stuff. Instead, lawyers for both sides are fighting over what qualifies as a public record. Attorneys for the San Diego water agency want to know how Metropolitan calculated its rates and other charges.