Next time there is a knock at the front door, it just might be the head of the Environmental Protection Agency waiting to deliver a message.

EPA Administrator Gina McCarthy dealt a warning Wednesday to Americans who do not place environmental stewardship above everything else.

"If you are selling to somebody a product, and you can assure them that that product was produced in the most environmentally responsible way, I will guarantee you that they will value that product more highly," McCarthy said at the 2015 GreenGov symposium at George Washington University in Washington.

"I can guarantee you because if they don't, I'm going to knock on their door and I'm going to tell them why they are mistaken," McCarthy said, pointing at the audience.

Speaking for almost 15 minutes, her remarks largely focused on how cutting carbon pollution drives "smart investment" and the EPA's efforts to implement the Clean Power Plan to reduce greenhouse gas emissions from power plants, the centerpiece of President Obama's plan to fight climate change.

McCarthy defended the federal processes, rulemaking and purchases EPA has made over the past decade to combat climate change. She said they have made the U.S. stronger, acting as tools used to "reflect the value of our government, as we see it for the people that we serve."

She said the power sector is adapting to lower carbon generation and that the government underpins investments made by utilities and businesses with rules to foster innovation.

"That is how government works — we tell you what you can do today. We give you the flexibility to get it done yourself and we send a long-term market signal that is going to open up innovation moving forward."