What level of DI water is it. A manufacturing plant in KC was dumping DI 10 waste water into the sewer. It ate the sewer pipe. That was years ago and I had to design the neutralization system. You need to find out what grade of DI water you have and then find out how active it is in the system you have. One thing I do remember is that stagnant DI water goes septic pretty quick. Wish I could help more but it's been too many years.
