A quarter-century ago, San Diego and its suburbs imported 95% of their water supplies. Thanks to investments in desalination and other efforts to boost supplies, that figure has already dropped to 57% and is projected to fall to just 18% sometime in the next two decades.

San Diego has gone from being one of the most vulnerable areas of California during drought to one of the best prepared — and in so doing has become a model for the future of water use in cities.

Water conservation in San Diego County and across the state bounced back substantially in March after a weak showing during several previous months.

On average, California’s urban water users saved a robust 24.3 percent in March as compared with just 12 percent the month before. The savings are measured against corresponding months in 2013, the benchmark year set by Gov. Jerry Brown’s emergency drought order.

Water suppliers in San Diego County saved an average of about 17 percent in March. That was a significant improvement from February, when many districts didn’t conserve any water or increased their consumption.

Another bout of rainy weather is expected to drench the Southland beginning late Wednesday. According to the National Weather Service, a low pressure system will bring rounds of showers and thunderstorms into Southern California over the next few days.

Weather experts have forecast drizzle on Wednesday growing to a 40-percent chance of showers Thursday evening and increasing through Sunday across the San Bernardino area and the Inland Valley, according to the NWS website. “A few thunderstorms could occur… especially Friday when the system is overhead,” according to an NWS report.