Oily stuff from water pipe

[gwyc]

Has anyone seen oily substance below a water pipe (eg on garage floor) growing slowly which indicate there is some oily substance dripping from the pipe?

[LazyPup]

When water drips from a pipe onto a concrete floor it is common to find an oily slippery substance. That is not an indication of the water quality, it results from bacterial growth supported by microscopic organic dust materials on the concrete and the water. When discovered is should be washed down with laundry bleach to kill the bacteria.