ECO - utility settings per lot - how does it work?

It's to add utility points to your home. Add positive and you have utility surplus (use them without raising your bills, to be able to use plumbing and electronics off-the-grid, or sell them for money) or add negative and you'll see your utility bills go up.

For example, if you choose water positive 50 (large), you'll get 50 water utility points to be used by plumbing. These stack, so click on it 5 times and you'll get 250 water utility points.