I've done lots of Googling on this subject, which led me to check many things in my attempt at resolving the trouble. However, the problem still exists, and I am still left with questions.
Situation:
- 2 story house with basement half above grade (so it's like 2½ stories)
- A single roof vent for all drains in the house
- House has 1½ baths: full upstairs, powder room in basement (both installed by builder
- House built 1988, no modifications to plumbing
- All downstairs drains are just fine. Toilet flushes properly.
- Upstairs vanity and tub drains a bit slow, but acceptable. Had problem last winter. Augering drain seemed to fix it. This time augering does not fix. Upstairs toilet flushes VERY slowly. Does not ever drain completely.
- Had toilet off today, snaked drain with 25' auger. No clogs found, no change in toilet behavior
- When toilet was off, 2 gal buckets of water poured down drain as fast as possible went down without problems or backing up
- When 2 gal was poured quickly down freshly re-installed toilet, the toilet still does not flush. Water rises, goes slowly down to resting level but no further. If I wait ten minutes, then pour 2 gal down, it may flush all the way, but lazily when it does
- No obstructions in toilet trap (checked when toilet was off)
- Jets in bowl are clear. Siphon hole is also clear and emits water when toilet flushes (felt with hand)
- Weather here has been off and on cold/warm. Currently nearly 40F and rainy. No snow on lawn or roof
- No trees near stack
Conclusion: The problem has GOT to be the stack, no? I'm out of other options.
Questions: The roof is 30 feet in the air. The roof pitch is steep enough, and wet enough, that wife does not want me up there just now. What does the inside of the stack look like, and can I just use my 25' auger inside it? If there's ice or other debris, will it be readliy visible with a light?
Thanks for any help.