3-ply, plumbing friendly

The last round of toilet paper that I bought was from Costco. Not because it was cheaper or because one package lasts 6 months, but because it was septic friendly. Septic Friendly. Exactly what I needed. It did last six months, and it was affordable, and while I can't tell how friendly it has been to our septic system (which I feel I should name for how much attention I pay to it), I haven't seen signs of complaining. Septic Friendly, perhaps, but also scratchy. Scratchy, prone to separation and each roll impossible to start for all the glue holding down that first piece. But I am still new enough to the whole country living thing that I feel obliged to sacrifice comfort for the greater good of septic health and the brand apparently is very environmentally friendly so there you have it. Scratchy toilet paper.
But after a rush on visitors, the stockpile dwindled and so suddenly it was time to buy toilet paper today. Off I went to my local Fortinos, local enough that it is a pretty rural Fortinos. If anyone is going to carry Septic Friendly toilet paper, you would think that this store would be it. Wrong. Oh there's the "green" version (referring only to recycled materials) but nothing with Septic Friendly. But then I see a line of Royale, bolding proclaiming that it is dye and fragrance free, biodegradeable and PLUMBING FRIENDLY. Dye and fragrance free - great. Biodegradeable - great (although isn't all toilet paper biodegradeable??), but plumbing friendly? What does that mean?? And to top it off, it is 3-ply. The luxurious softness. Can a 3-ply toilet paper possibly be Septic Friendly as well as PLUMBING FRIENDLY??
Of course I had to buy it. I had to buy it not because it was 3-ply (I'm still pretty suspicious that anything 3-ply is going to cheer up the little people in the septic tank) but because compared to just plain old 'green' (100% post-consumer recycled materials) the whole dye free fragrance free biodegradeable plumbing friendly thing begged me to give it a test.
So, here's to comparative shopping. It is remarkably soft, it really is. And because it is soft but more importantly sturdy, it seems like it goes a lot further. It flushes perfectly well down our low-flow toilet (with the super low-flow adaptor on the gasket), which is another good sign. I hope that the 'biodegradeable' part is true and quick - I hope their definition of biodegradeable isn't "within 10 years" or something. Did I mention how soft it is?
This first roll has sort of been like having a shower in the city... the luxury of not considering the impact of every action. But then I realize that even still I'm pretty in the habit of contemplating everything, and so no matter how soft or plumbing friendly the 3-ply is, I can't forget the impact it might have on the whole ecosystem that is our septic system (Steve? Bruce? Al?).
So I think I'm going to compromise. Tomorrow I'll hit Costco and pick up the oversized box of Septic Friendly toilet paper. Then I'll alternate it it with the decadent Royale rolls.... kind of like splurging on ice cream or tequila. But if I were ever to find out that 3-ply is just as 'septic friendly' as anything else, then there will be no turning back.
I would really like to figure out what "plumbing friendly" means, though.