Okay, so I know that I'm new to this, but I would have thought that it would be best to minimize the distance between the house to septic to leach field. On my property, one house is over 500 feet between these things, and the other is 250 feet. It's creating all kinds of havoc with fence planning. Why would this have been done? our soil is rocky, could that be part of the issue?
The soil engineer has to account for several issues when they design a septic system:
Percolation of the soil, which is, how fast does the soil in the area allow water to drain. This is both topsoil, and subsoil.
The other thing is grade. There has to be enough pitch so that they get 1/4 of an inch drop per foot so that pipes move the black and grey water along.
And the third is distance. It has to be so many feet from the well or surface body of water.
The fourth is depth to ledge rock. In Maine, this factor is often the most limiting because our soil is thin here. But it takes some depth to get the septic tank in, and pipes dug down for the leach field.
This is why your septic tank and leach field are where they are. I have no idea what those factors are in your system, but no soil engineer is going to make pipe runs long just because they felt like it. They either had to get away from ledge, had a spot that was a long distance away that had the proper draining soil, or grade was a factor. I do not know, but there was a good reason for it.
As for your fence, just locate where the pipe is, and do not put a fence post there. Move it two feet in either direction and you will be fine.
I got a grant back in 2008 from the USDA to put in a Heavy Use Area, That consists of a concrete pad for animals to be fed on and stuff. Anyway the USDA had to come in approve the spot for soil type, perculation and that kind of nonsense.
So these two USDA employees show up, take a look and say, well that level spot looks good. Now I am not too smart, but if I see a house on a 6% hillside, and there is a level spot, I pretty much know that that is probably the leach field. I can drive down the road and spot where the leach field is, it really is not rocket science.
So then these two brainiacs get out their shovels, then he comes over to me and puts his hand on my shoulder and says, "You should have a gravel pit here, there is nothing but gravel there."
I just nod. If these two guys, both soil engineers do not know the difference between rock broken by a mechanical rock crusher, and rock smoothed over by a glacier in the 4 years they went to college, me explaining that in a few sentences will never help. I just nod my head, and say, "yeah there is not much money in sheep farming is there?"
These are the sort of things farmers have to put up with. After awhile you just shake your head and keep your mouth shut.