/rant
OK! I'm pissed off enough again to post here rather than go ballistic and regret it later.
Yes, the root cause is the same as it usually is: Lack of friggin' common sense which seems to be innate here. I will skip most of the blah blah blah to keep my blood pressure down:
We have a sewage pump (required because of a previous major lack of common sense) which failed to turn on while washing clothes, and the water backed up into the washroom where we keep it. Blah, blah, blah. So, I investigate and find that the float is covered in bacteria and GREASE which was weighing it down. A poke with a pole and presto - the pump turns on. Blah, blah, blah. The submersible sewage pump has a 2" outlet which, down the pvc line, tapers to a 1 1/2" pipe. Water should normally be gushing out, but it is barely flowing as much as a 1/2" pipe. Blah, blah, blah. So, I investigate and discover the Mrs. must have been pouring GREASE down the drain the entire time we've been in the house (almost a year now). WTH?!? So, I quizz her and she fully understands that hot grease and cold water form a solid. So WHY 'O FRIGGIN' WHY - knowing that - would you pour grease down the drain? Answer: "Well you didn't tell me NOT to do it!". *Slapping MYSELF because I love my wife*
So, fellas. TODAY - TELL your wife/girlfriend or whatever NOT to pour grease into the sink!!!
Luckily, I am discovering/realizing this now rather than when the pump blows up from the back pressure of NO water flowing out or when the sink isn't draining because of all the muck inside. I will be saturating our waste lines with baking soda today, then run a whole lotta vinegar through them to clean the PVC drains as much as possible that way, but it is likely I will also have to get a professional involved to run an electric auger through the lines at a cost of THB 1,500 (from her money, not mine).
/endrant