Indiana Jones part 4

Indiana Jones fan, That's me! I liked the 4th. I thought it was very good. Much better than the "prequels" to the star wars movies. I hated those.
So within a city water system every time someone flushes a toilet, electricity could be generated. Every time some one rinses a dish, electricity could be generated. Anytime any one uses water pressure, electricity could be generated. With as simple as something as a back-flow preventor(which is already mandated,) we could have a generator that produces electricity every time flow is produced in a city water system. This is still a thought that is based on "little things", and contrary to popular belief the little things do matter and most times it is the little things that matter most.
Attic heat could generate electricity. Every attic creates heat, that is why it is recommended that the bulk of insulation is placed between the attic and ceiling. I know that they say it is to keep heat in, but I have been in a lot of attics and it is just as hot in winter as in summer. Homeowners install fans that consume electricity to dissipate heat. Why not instead use the attic itself as a large heat exchanger?
Enough for now. Much more to come...