Yes. Homeowners can experience an unusual problem of a pinkish substance on bathroom fixtures that is very persistent and appears in the shower, the sink, and especially along the waterline of toilet bowls.
This pink residue is less likely a problem associated with water quality than with naturally occurring airborne
bacteria. The bacteria produces a pinkish film, and sometimes a dark gray film, on surfaces that are regularly moist, including toilet bowls, showerheads, sink drains, and tiles. The problem also more commonly occurs in humid regions of the country. To determine the exact species of bacteria would require lengthy and costly laboratory testing, and for those reasons most homeowners are reluctant to have the tests performed. Although the exact species of bacteria is not known, most experts have concluded that this pink staining is most likely from the bacteria Serratia marcescens.
Members of the Serratia genus are essentially harmless organisms that produce a characteristic red pigment. These bacteria thrive on moisture, dust, and phosphates and are widely distributed, having been found naturally in soil, food, and also in animals. The conditions for the survival of Serratia marcescens are minimal, and the bacteria may even feed upon itself in the absence of other nutrients.
Many times, the pinkish film appears during and after new construction or remodeling activities. The dirt and dust stirred up from the work probably contains Serratia bacteria. Once airborne, the bacteria seek moist environments to proliferate. Some people have even noted the pink residue in their pet`s water
bowl. It causes no apparent harm and can be easily cleaned off. Others have indicated that their experience with this nuisance occurs during a time of year that their windows are open for the majority of the day. These air- borne bacteria can come from any number of naturally occurring sources.
The best solution to keeping fixture, sink, and bathroom surfaces free from this bacterial film is continual cleaning. Chlorine bleach can be periodically stirred into the toilet tank and flushed into the bowl itself. As the tank refills, more bleach can be added. Three to five tablespoons of fresh bleach should be all that is necessary. A toilet cake that contains a disinfectant can keep a residual in the water
at all times. The porous walls of a toilet tank can harbor many opportunistic organisms.
Cleaning and flushing with chlorine will not necessarily eliminate the problem, but will help to control these bacteria. Keep bathtubs and sinks wiped down and dry to avoid this problem. Using a cleaning solution that contains chlorine will help curtail the onset of the bacteria.