School districts across the County are requesting water testing after dangerous levels of lead were discovered at a San Ysidro elementary school.
Health experts say the schools most likely to have unsafe levels of lead in drinking water are those built before 1986.
NBC 7 mapped out where schools in the county built before 1986 are located, and found they are spread out throughout the region.
Clusters of schools built before 1986 are located not just in the South Bay, but also in San Diego neighborhoods like Clairemont, Scripps Ranch and Tierrasanta, the map shows.
Dina MacDonald has a family member that goes to Tierrasanta Elementary.
It's one of the approximately 447 schools across the county built before 1986.
"I think the more years that go by and we see these facilities that were built more than fifty years ago, a lot of them," MacDonald said. "I'm sure there's a lot of other things going on in those schools that probably need to be addressed but like everything you kinda put it off and don't think about it until there becomes a problem."