Which comes first?

[grover]

Which should be done first or does it matter?  Cabin, septic, or cistern?

Side question about the cistern.  I am building on a slight slope.  Should the cistern be a little on the downhill side so when I drain the lines it all flows downhill? 

[mgramann]

I would start by planning where the septic system will go, and what type is required.  Then determine cistern location, which I would always locate at a higher elevation than the septic, so dirty water could never make its way to the clean water.

I would however, wait to install both if possible, until the cabin is built.  This way, you don't risk a delivery vehicle putting weight on either system.

[Redoverfarm]

Which should be done first or does it matter?  Cabin, septic, or cistern?

Side question about the cistern.  I am building on a slight slope.  Should the cistern be a little on the downhill side so when I drain the lines it all flows downhill?

I agree with mgramann.  You need to locate the location for the septic and field probably more importantly than the cistern.  Make sure that the location of the field will perk.  Otherwise you might build the structure and find out that the septic will not work where you had anticipated.  Site planning is crucial. 

[grover]

Perk test has been done and a site approved.
I probably should wait because the septic line from the house has to run under the driveway.  I never thought about damage to it from heavy equipment.
The cistern will probably go on the other side of the cabin, slightly downhill.  Hopefully that will make draining the lines in freezing weather easier.

[grover]

I will want to get them both in as soon as it is under roof.  We plan on "camping in" on the weekends so we don't have to drive back and forth so much.  The bathroom will probably be the first thing done.  This will also make the weekend stays much more comfortable while finishing the inside.

[Redoverfarm]

Perk test has been done and a site approved.
I probably should wait because the septic line from the house has to run under the driveway.  I never thought about damage to it from heavy equipment.The cistern will probably go on the other side of the cabin, slightly downhill.  Hopefully that will make draining the lines in freezing weather easier.

I would suggest that you run your septic line through a piece of Sch 80 under the driveway portion.  Normally 4" is typical for the septic so a piece of 6" Sch 80 should work.  If at a later date and time you ever decide to pave/concrete you can replace that section w/o damaging the existing drive.  I had even ran a piece under mine before I had it paved for future use( )  just so I would have a way to get elect, water or what ever on the other side.