The United States signed a memorandum of understanding Thursday with Mexico, launching a permanent solution to end the Tijuana River sewage crisis. Upon arriving in Mexico City on Thursday morning, Environmental Protection Agency Administrator Lee Zeldin met with Mexican officials to discuss what Zeldin called a 100% solution to end the crisis.

The United States and Mexico on Thursday reached an agreement aimed at finding a permanent solution to a decades-long sewage crisis, in which Mexican sewage has flowed into the Tijuana River and acros...