Do you mean like part of a rainwater drainage system. A hole in the ground
filled with drain rock.

No, they do not fill with biodegradable material then redistribute through
leachfield pipes, they just silt up over time and become useless. Nothing
will remove silt from between rocks besides digging it up and washing it
out.



"Vince" wrote in message
...


Is there any need to add chemicals to the seepage pits / drywells ?

What kind of chemicals would be used, if YES ?


Are chemicals used only to supplement a septic tank system ?