I like your ditty yer tis, but I would probably amend it to include the worst offenders:
All of us with septic tanks,
Give to you our heartfelt thanks,
For putting nothing in the pot,
Thats isn't guaranteed to rot.
Moist wipes are bad, condoms too,
Feminine products are taboo,
With your kind cooperation,
We'll keep our tank in operation.
Kleenex tissues are the least of my worries, and most properties are non-smoking (who puts fag butts down the loo? Apart from Wayne and Waynetta Slob? Surely not) so moist wipes (whether toilety wipey things or make-up remover wipes) are the biggest potential problem I would have thought followed by feminine hygiene products. I've not ferreted around in my septic tank though so I have no statistics on that!!