An important lesson

Acting with too little data and not even taking advantage of all the data you have can lead to serious errors. Bear with this long post. There are a few neat "punchlines".

 This weekend our guest noted water dripping from the first floor bathroom ceiling. He said it was luke warm. I immediately went to the basement and closed the hot water shutoff valve to the upstairs bathroom. The drip continued. I rushed and shut off the cold water valve. The drip stopped shortly afterward.  I opened the hot shutoff and no further dripping occurred. I surveyed the plumbing arrangement for the upstairs bathroom.   The cold water feed came up through a first floor closet. At the first floor ceiling it had a horizontal branch which went toward the sink while the line continued vertically to the shower. I went to the upstairs bathroom and noted that the feed to the toilet tank was at floor level. None of the lines I could touch felt wet. The piping ( tubing) was of chlorinated polyvinyl chloride (CPVC). My conclusions were: the line to the toilet branched from the horizontal line in the floor; the leak was most likely at the "tee" fitting where this line branched off; the best way to reach it was through the ceiling where removal of a small piece of metal ceiling would give me good access.

Results ( why my conclusions were faulty):

1) After spending well over an hour ( not counting the time searching for tools) carefully removing the cove molding and the many nails holding the ceiling sheet in place and bending it back, it was obvious that the original plaster ceiling was intact even including some stenciling, and had never been entered by a plumber.   Reaching the the pipe through here would require destroying the original fabric of the house and a lot of work and mess. So access through ceiling was a bad conclusion.

2) Went to the upstairs bathroom and looked at the floor. The cuts the plumber made were so obvious and obtrusive anyone with any sense would have known immediately that this was the way to gain access to the pipes.  So I pulled out the vanity floor and pulled up the three floor boards the plumber had used for access and exposed the horizontal line I mentioned earlier.  There was no tee in the line to feed the toilet. So the conclusion about how the line to the toilet ran was wrong as well as the conclusion about where the leak was. I revisited the vertical line and reaching up into the space above the closet ( remember the closet where the vertical line ran?) I found where that line branched off with one line feeding the bath/shower, and the other  running in the wall and then down to the floor to connect to the toilet.

3) Now having the horizontal line fully exposed I was ready to find the leak. I asked my wife go to the basement and open the cold water feed valve. She did. Nothing happened. In short, there was no leak!!!

What had happened was she had taken in a shower in the upstairs bathroom without tucking the curtain in properly and some of the water had seeped through the floor to the first floor  bathroom ceiling. The fact that the dripping stopped when I closed the cold water feed was just coincidence.

I just hope I remember this lesson and  that maybe some of you will learn to be less hasty in drawing conclusions before gathering and analyzing all the available data.