# septic system fill calculation

## septic system fill calculation (post #206177)

Building septic leach field. Need help calculating total yards of stone and sand for system.

System is 20' x 40', open system. laying 160' of leach piping in 2' x 3' trenches. Need to cover with 2' of 1 1/2 washed stone and top off with 1' if washed sand.

Need to order stone and sand but geometry not my fav subject.

Stone will be 2' x 2' in trench and topped off with 1' sand.

my calculation is;

Stone = 2' x 2' = 4' x 160' = 640 divided by 27 (cubic ft. in cubic yd) = 24 cubic yards  but seems like alot.

Sand appears to be 12 cubic yards ???????

Thanks,

Chuck

### Chuck (post #206177, reply #1 of 2)

If it were me, I'd ask a hauler how much stone.

You'll be thinking in cubic ft, but the stone is sold by the ton.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.

### So people in your area still (post #206177, reply #2 of 2)

So people in your area still use the "conventional" drain rock and PVC perforated piping? Around here they disappeared over ten years ago and have been replaced by "chamber" systems like this:

Have you considered these? No drain rock, and no "dead spots" on your lawn because of poor sub-soil.