[dharmab]

Water towers are already used that way- water is pumped in during off-peak time and used during peak time.

[mikepurvis]

Right, but that's about maintaining pressure and supply when everyone wants a shower at the same time in the morning, not about harvesting the energy of it all flowing downhill.

[ClumsyPilot]

Pressure is energy

[bigiain]

Nope.

Energy is force times distance. You need to know more than just pressure to calculate energy.

(A bicycle tire at 120psi has a lot less energy than a truck tire at 90psi.)