Padre Dam Municipal Water District, already charging among the highest water rates in the nation, is proposing yet another five-year rate increase that officials say is necessary to maintain the agency’s services. In a 12-page notice sent out to all of Padre Dam’s 24,000 customers, the district outlined the rate increases depending on use, and the rationale supporting the increases. Starting in November, an average residential customer in Padre Dam’s district should expect their combined water and sewer monthly bill to rise to $154.75, up $3.74, or nearly $45 annually.