One of the most expensive capital projects in city history — a massive water-recycling plant — is costing almost $100 million more than expected because San Diego Gas & Electric is declining to pay to relocate its equipment to make way for the project. At the request of Mayor Kevin Faulconer, the San Diego City Council has agreed to pay SDG&E $35 million to move gas and power lines so work can start on Pure Water San Diego, the $3 billion plan to promote water-independence by treating wastewater and returning it to city taps.