He is essentially using his own money to do what the local and state governments should have done. His discretionary funds could have been used to buy equipment

He is essentially using his own money to do what the local and state governments should have done. His discretionary funds could have been used to buy equipment for his lab in order to help him get research grants. Instead, they were spent to do water testing in a different city and in a different state. He isn't going to receive any research grants or meaningful scientific publications out of this, which is essentially the job of a university professor. That's why it is portrayed as such a sacrifice.