Published on September 18th, 2013 | by Henri0
Flushing upstairs toilet causes bubbles in downstairs toilet
Q. I replaced my upstairs toilet with an American Standard gravity flush. It flushes very quickly but this causes the downstairs toilet to bubble up to relieve the pressure. Will putting a vent outside just before the septic tank correct this problem?
A. The sketch you sent me shows that your plumbing system is not properly vented. The downstairs toilet is not tied to the roof vent. If this did not occur before you installed the new toilet, it is probably because the older toilet flushed much more slowly. The American Standard 1.6 gallon toilets use a different flushing system and, as you have experienced, it is very fast and powerful.
Installing a vent outside just before the septic tank would allow septic gases to escape and stink up your yard. That’s not what you want. You should have a licensed plumber correct the venting system’s deficiency. There are several ways to do it; perhaps the plumber can install a Studor vent, an interior vent that equalizes the pressure in an unvented fixture and can only be used where there is a roof vent for the rest of the plumbing.by