A long-awaited Montecito Water District rate study, planned for release this May, will not be finished until later this year, officials said this week.

The study can’t proceed until the district finishes negotiating the terms of an agreement for buying into Santa Barbara’s desalination plant, said Nick Turner, the district general manager.

Still to be determined, he said, are the quantity and cost of a potential city supply for Montecito: it could be enough water to meet as much as 35 percent of Montecito’s demand, with a price tag of up to $4 million, every year for the next 50 years.

Negotiations with the city began in October 2016.

“It’s time to wrap it all up, hopefully before the end of August,” Turner said.

The rate study also will reflect the $200,000 cost of looking into whether Montecito’s groundwater basins are large enough to hold a supply of recycled water; and the $200,000 cost of determining whether they are in overdraft, said Adam Kanold, district engineering manager.

Not included, he said, is the cost of building a plant to recycle Montecito’s wastewater, either for irrigation or injection into the ground. Those projects have been estimated to cost between $5 million and $32 million.

The district’s annual budget is $20 million.

Once the rate study is complete, officials said, the board will hold public hearings and vote on whether to buy a long-term share of Santa Barbara’s water supply.

If the project gets a green light, Santa Barbara may have to expand its $72 million waterfront desalination plant, said Joshua Haggmark, city water resources manager.

In addition, he said, the city would have to build a $12 million “conveyance” pipeline to help carry desalinated water to a buried tank at the Cater Treatment Plant off San Roque Road. From there, the water would be mixed with other city supplies and shipped to Montecito through the South Coast Conduit, a pipeline that goes to Carpinteria.

Because Montecito has not yet voted on the project, the city this week withdrew its application for a $1-million state grant to help pay for the conveyance pipeline, Haggmark said. The deadline is in August, he said, but the city can apply again next year.

Whether Montecito purchases city water or not, Haggmark said, “we’re good with it, either way … It’s not going to be a windfall for the city. It’s a fair deal.”

— Melinda Burns is a freelance journalist based in Santa Barbara.