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In the past several months, three schools in the San Diego region have revealed the presence of alarming levels of lead in their drinking water. Lead is unsafe at any level and it is especially damaging to children’s brains. Now, San Diego Unified and other school districts across the county are moving to test many more schools. Here’s what we know and what we do not. At La Mirada Elementary School in San Ysidro, samples taken last fall found alarming levels of lead coming from eight drinking fountains.

The California Natural Resources Agency (CNRA) and the Salton Sea Task Force released a ten-year plan to protect habitat and human health for the state’s largest inland lake that has been plagued by decreased flows, drought and rapidly increasing salinity and pollutants. Exposed playa, or lakebed, along the sea’s shores create toxic dust, as many locals have developed respiratory illness in the Imperial Valley. Tiny particulate matter is exposed on the playa and carried through the air as dust into Riverside and Imperial Counties.

On January 26, San Diego County’s water authority exulted that the drought was over. On March 22, the New York Times wrote, “We have some good news on the California drought.” The huge snowpack in the Sierras portends more water. Countywide, San Diego’s reservoirs are filling up. People are cheering. But there’s little joy in tiny Borrego Springs, in the northeast portion of the county. It doesn’t have reservoirs. It gets its water from an aquifer, or permeable rock that can transmit groundwater.

More than half off all beaches in Southern California could disappear by the end of the century due to sea-level rise, according to a study published Monday in the Journal of Geophysical Research. As a result of sea-level rise, up to 67 percent of beaches from Santa Barbara to San Diego could be completely eroded back to sea cliffs or coastal infrastructure by 2100, according to the report from the U.S. Geological Survey.

Two fault zones that were thought to be separate actually make up one continuous fault system running through San Diego, Orange and Los Angeles counties, according to new research. If all the offshore and onshore segments of the so-called Newport-Inglewood/Rose Canyon fault system were to rupture at once, a magnitude 7.4 earthquake could seize the region.