PLANTS GROWING BY LEAPS AND BOUNDS NEAR LEACH FIELD

(Carmel Valley, CA)

Oleanders, a Century Plant (agave)that has grown 9 feet tall ad wide and a Canary Island Palm that's about the same are FLOURISHING near my leach field.Nothing else on my alkaline soil property is growing with such vitality.

FIRST OF ALL, THANK YOU VERY MUCH FOR TAKING YOUR TIME TO READ THIS.

My question: If any of their roots get into my leach field, I fear that
I may have to build a new leach field which, around here, runs $50,000 or so. This is enough for me to go down there right now and move and/or cut them down. But I'm Mother Theresa with plants (I look out through their eyes and feel their elation for life) and so I put it off plus I'd have to
hire it done and it would be a big job.
Here are the particulars in case anyone has the expertise to advise me.
(Please, if you're guessing, don't advise though I certainly appreciate your
desire to be helpful.)

The leach field stretches out in a long trench under a 45 degree hill. Exact location is unknown but I know approx. where it is give or take ten feet or so. Now if we follow the supposed location of the leach field up to the surface of the 45 degree hill, I estimate that this surface area is around 8-10 feet from the top where it levels off onto a plateau. Running along the edge of this plateau are my 8 oleanders (3 1/2 feet x 3 1/2 feet each - not big for an oleander but big and unusually healthy for this alkaline property). TO LOOK SO HEALTHY, I THINK THEIR ROOTS MUST BE TAPPING INTO THE LEACH FIELD (However, I did read your 5-10 feet above--it's hard to know when their roots are going down - when I researched it, I found that oleanders don't have a big root system.)

Around eight feet behind them (going away from the leach field) is MY GIGANTIC CENTURY PLANT THAT LOOKS LIKE ITS GOING TO TAKE OVER THE WORLD. COULD ITS ROOTS BE TAKING OVER THE LEACH FIELD PIPES AND MY BANK ACCOUNT? The same is true for my palm which is right next to my century plant and it too is growing at a phenomenal rate - 8feet by 8ft. I catch my breath when I look at the two of them. In regard to the century plant with its sawtooth
edges and sharply pointed (leaves?), I actually feel alarm.
I'm beginning to think, to be on the safe side, I should cut down the century plant, move the oleanders and transplant the palm which is going to cost $$$ because I can't do it myself BUT IT'S BETTER THAN HAVING TO GET A NEW LEACH FIELD. CAN ANY KNOWLEDGABLE PERSON PLEASE ADVISE? I WOULD BE SO GRATEFUL. DIANA