Elon Musk said on Wednesday that he would help pay to fix the water in every house in Flint, Michigan, that has water contamination levels above federal guidelines.

"Please consider this a commitment that I will fund fixing the water in any house in Flint that has water contamination above FDA levels," he said on Twitter. "No kidding."

On Tuesday, Musk said he had already helped Flint, but he didn't elaborate.

Elon Musk said on Wednesday that he would help pay to fix the water in every house in Flint, Michigan, that has water contamination levels above federal guidelines.

"Please consider this a commitment that I will fund fixing the water in any house in Flint that has water contamination above FDA levels," he said on Twitter. "No kidding."

Musk was responding to a Twitter user who said he had been told Musk wouldn't be able to help bring clean water to Flint, whose residents have grappled with lead-contaminated water since 2014. The Environmental Protection Agency regulates drinking water in the US, while the Food and Drug Administration regulates bottled water.

On Tuesday, Musk said he had already helped Flint, but he didn't elaborate.

Separately, Musk also offered in recent days to assist the Thai government in its attempt to rescue 12 boys and their soccer coach from a cave; they were all rescued alive this week.

Musk sent a child-sized submarine and engineers from two of his companies — SpaceX and The Boring Company — to Thailand, and he traveled to the country amid the rescue operation, though the submarine was not used.

Also on Wednesday, Musk expressed frustration at those who criticized his efforts to help with the rescue, saying it had "shaken my opinion of many people."

He added: "We were asked to create a backup option & worked hard to do so. Checked with dive team many times to confirm it was worthwhile. Now it's there for anyone who needs it in future. Something's messed up if this is not a good thing."