It's a bug, and you do it like this: 1. Open up Powerplants dialog and close it with X.
2. Open up rewards dialog and close with X.
3. Open up Garbage disposal and close with X.
Now you get free buildings.
Free water: 1. Start a new game and build only one building.
2. Run pipes from that building to the nearest neighbor.
3. Make a connection and wait for a water deal to be offered.
4. Accept the deal, regardless of what the price is.
5. Wait until the end of the month.
6. Bring up the cheat box and enter "terrain one up." All buildings on the map will be removed and your deal will appear to be terminated.
7. Rebuild a new water connection at the same point where you originally made the connection.
When you rebuild the connection at that same exact tile, the water will still flow into your city, but since the deal has been terminated, you will not be charged for the water supply!
As copied from simepage.net