The Problem with the Plumber...

Since January 24th we have had 5 visits of a plumber.

Visit 1: Evaluation of problem, trying to install a new faucet. Wrong faucet was purchased - return the following day
Visit 2: Installing the new faucet - sink is not draining. Promise to visit another time.
Visit 3: Installing a new pump for the sink. 4 hours and €400 (paid by landlady) later pump is working

Three days later...
We do our dishes and have the laundry machine on. Suddenly the kitchen floor is flooded with water.
The following day...
We do our dishes and have the laundry machine on. Suddenly the kitchen floor is flooded with water... again! Water is also coming out of the wall in front of my room!
Later that day...
The laundry machine is not on. We do our dishes - everything is flooded again.

The following day...
Visit 4: The plumber is back at 10 a.m. - after 30 Minutes claims to have fixed the sink. Everything works until 15 minutes after his departure. The kitchen is under water again. I find a leak in the plumbing and call our tralator again to let our landlady know.
Visit 5: Two hours later, landlady and plumber are back. I show them the problem - the plumber fixes it.

Later that day, after university...
I check the sink. Everything seems to be fine.. 10 minutes later, the kitchen is under water. Take the whole kitchen cabinet apart to find the new leak. Found it. Plumbers will come back tomorrow - let's see if he will be able to fix this problem - once and for all.

In the meantime I am reevaluating my carreer goals: Should I become a plumber and safe Hungarian households from bad plumbers?