Several government agencies, including the FBI, the EPA and the Cybersecurity and Infrastructure Security Agency (CISA) — the agencies making sure sewage and other biohazards stay out of your drinking water — put out an advisory last week highlighting cyber threats to local water and wastewater systems.

The warning cites several cyberattacks over the last few years. Like one in Oldsmar, Florida, where someone tried to hack in and dump extra chemicals in one municipal system. CISA is urging water and wastewater facilities to plan for, and get ready to block, these attacks.

Kim Zetter, a cybersecurity journalist and author, says there is a resource issue. The following is an edited transcript of our conversation.