steamup wrote:FYI, based on the info you posted, do not be surprised if the engineer states that your entire system is marginal at best but more likely slightly undersized. Your perc rate is ok but not great. You use a little more leach field than what you got. Sandy soil plugs quickly.
If you have the room, a second 500 gallon tank after the 1000 gallon tank would create a larger capacity, two compartment tank system. The filter could go in the outlet of the second tank. I have also seen filters for distribution boxes. I am not a fan of dosing systems if they can be avoided but they are required on some systems to even out the flow to larger leach fields. I don't know if a dosing system is applicable here.
If only the far end of the leach field is wet, was the field installed level?
If you have two runs of chambers, do you have a distribution box? Is the box distributing evenly?
The engineer has made exactly those comments in passing but has reserved his conclusion until he studies his data and formulates a plan. So he says.
The second tank sounds like a good idea to me. The engineer has floated the idea of replacing the tank but I don't see why we have to do that. I think modifying it or adding a second tank as you suggest is ideal. The digger thinks the house breaching is too low in the ground (18" o.c. of 4" pipe, from the surface).
The "lower run" of leach field is wet at the surface the whole length. 0 I say "lower" only because the surface varies over the leach field by one foot from highest to lowest ground cover, the wet end being just 10 or 11 inches below the surface). The D box has not been checked because the tank is full (up-the-riser full) and I avoided the suggested repairs from the local digger/septic guy (he just keeps wanting to pump but I played that game last time and it cost me $750)and the local drain guy and went directly to the engineer. I just don't have any confidence in the local digger or drain guy. They too were not confident.
The local digger/septic guy has a lot of experience but not at diagnosis, only digging. The drain guy didn't believe his power jet would clean the vaults. So I abandoned them and went to the engineer. The engineer was confident that the system had failed and because it was very near the last failed field, it was time to move it. His information on the septic tank is base on information from me. The digger thinks the septic tank can be modified but doesn't like the depth. Both now agree that the load is too heavy for the size of the field considering all factors of load and soil. I agree with that but also think my ignorance and the tank design contributed to early failure. Now I am educated (thanks to this board and others), I think a new leach field is what the doctor will order but I want a new septic tank, or modifications to it, which could be a second smaller tank with filters. The new system will have to have a pumping chamber because of the grade to the leach field. The other issue is the water softener salt. One way or another I will prevent that from going to the septic system.