Why does current stay the same through different pipe sections?

[asdf916]

Homework Statement

Homework Equations

I suppose the energy density equation applies here:

(P2-P1) + pg(y2-y1) + 1/2p(v2^2 - v1^2) = Epump/vol - IR

and

I = Av

The Attempt at a Solution

My initial thought was that the current is the same. But then, since current is Av, I was second guessing myself that maybe the velocities are different. Any help's appreciated!

 

[asdf916]

Also, I'd appreciate it if you guys can help me on these

My guess was that the sewer gas is less than 1 ATM.

My guess is that the pressures are the same. Using the same energy density equation on the first post, I could eliminate the KE, Epump, and IR. That leaves the pressure and the PE. Since it's measuring the same height, the pressure's the same. Is this correct?