Cheaper recycled water is coming. But your water bill will still go up. Here’s why.

Three communities – San Diego, Oceanside and parts of East County – are entering the era of recycled water, at a crucial moment for local water politics. How that gets sorted out will be reflected in San Diegans’ water bills.

A decade ago, amid worries about the impact of drought on water supplies, those San Diego municipalities turned to recycled water, that is, turning sewage into drinking water. One local city, Carlsbad, also has a desalination plant, which turns seawater into drinking water.

All those recycled water projects now are coming to fruition. But angst about drought has been overtaken by concern about the rising cost of water from the San Diego County Water Authority, which sells water to 22 cities, water districts and other member agencies in the county.

In the past two years, the water authority’s rates have grown by 23%.

Annual rate hikes are now expected to be more modest, but they’re still forecasted to rise anywhere from 38% to 65% over the next decade, according to a new long-term financial plan the agency adopted last week.

Why is this happening? What do the new water technologies change? We try to explain.

Q: Why is the water authority’s water so expensive? 

Over the years, the water authority has secured a diverse supply of water for the region, at a time when other parts of California face shortages.

About 50% of the county’s water comes from the Colorado River under a 2003 ag...