Plumbing Problems

If I were an unschooler or even a relaxed homeschooler I would be running to the library for books on plumbing, waste water, valves, something. Or maybe I would research on the internet or better yet plan a field trip to Obi's (Germany's version of Home Depot) or the wastewater plant.... but instead we will stay out of the plumber's way when he is here for probably the sixth time tomorrow.
Today he put blue food coloring in my neighbor's toilet (she's on the third floor) and flushed; within 10 minutes I had (see pic) blue in mine (way down on the first floor). So tomorrow (while the water is off anyway for other repairs - they're installing a system to prevent standing water from seeping into the drinking water system) the plumber will be taking apart the tiled bathroom wall to supposedly fix the problem (this is not the first time I've been told it would be fixed) - I think something was said about raising something (I hope not the toilet or I'll need a stepstool) about 3cm. I told them they HAD to finish tomorrow since we go on 'holiday' (that's European for vacation) early Thursday morning through until the following week. And they said they would be done since they are leaving Garmsich on 30 November.
Sigh, I'm not holding my breath. Actually I will need to hold my breath since my bathroom will have that stinky workman/smoking odor (my apologies to smokers but the stench is strong and he was only here for 5 minutes today). Going to put air freshener on my shopping list (wait, I don't want to shop the day before Thanksgiving - guess I'll just open windows despite the freezing temps)