It’s hard to pin down how many billions of dollars the city is planning to spend on a new water recycling system, but it’s clear costs are rising – by billions of dollars. Back in 2015, the city of San Diego expected it would get about a third of its drinking water from recycled sewage within 20 years and could do so for about $3 billion in construction costs. Now, the city is looking to spend no less than $4.8 billion and perhaps as much as $9 billion on the project, according to city financial documents, including previously undisclosed internal estimates from the Public Utilities Department.