Basically, in 1996 we setup a program to make it easier for states to get federal money for water improvements, either via long term loans or grants.
The EPA then doles out the money, and it trickles back over time from loan repayments. That’s why with $21 billion in funding they’ve provided $41 billion in investments.
Periodically Congress adds some more money to the fund, but it’s largely the feds turning the massive one time costs of these projects into reasonable long term investments.
The Bipartisan Infrastructure Law dumped something like $50 billion into that fund, which is a lot more than it usually has, and $15 billion of which is allocated to lead pipes replacement.
After a round of assessments of pipes and applications from different water providers, the EPA put together a $3 billion package of the most high priority projects that can get started this year.
Then Biden signed the order to issue the round of funding according to EPA recommendations.
This is more like the first big paycheck after getting a new job than winning the lottery.