The cost of water has over last two decades risen dramatically across San Diego County as a result of investments in desalination, ongoing maintenance, ever-increasing energy prices and unprecedented conservation. However, not everyone’s feeling those impacts equally. Rates vary considerably among the region’s two dozen local water agencies, according to an analysis done last year by the Otay Water District. For example, a typical 1,100 cubic feet of water costs about $90 a month in the city of San Diego, compared to nearly $137 in the Padre Dam Municipal Water District.