Howdy, I don't know a thing about Pomegranate trees, but I do have figs; and yes, some of those fig ‘clumps’ are between my septic drain lines... If your septic tank is like mine (or most) it has a 'tight line' from its outlet to the first distribution box in your drain field (the line from the house is also tight). Unless you've a leak at your tank, or those ‘tight-lines,’ nothing should know it's there...

If the trees are near a leach line or in the drain field there could be problems. When I had my drain field dug the installer and the county sanitarian had a list of trees that were known to invade the lines; they both claimed my existing fruit trees were good neighbors and should not be problems. The drain field was actually designed around them. Since then I've replaced three of those trees with figs. I haven't asked… maybe you'd do it for us " title="Wink" /> Call your County / City septic official; ours is called a 'Sanitarian,' and ask him / her -- then let us all know!