Usually this 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 grow. These airborne bacteria can come from any number of naturally occurring sources, and the condition can be further aggravated if customers remove the chlorine from their water by way of an activated carbon filter.
While all water utilities are concerned about the quality of the product they are supplying to their customers, they cannot guarantee water quality once it leaves the pressurized distribution system and enters the customer's plumbing system.
Rotten Egg Smell From Drains
Bacteria growing in sink drains can make hydrogen sulfide gas (“gas”), which smells like rotten eggs.
When water runs down the drain, the gas is pushed out where it can be smelled. A cup of household bleach poured down the drain will help kill the bacteria and take care of the smell. Water heaters can also harbor bacteria that cause rotten egg smells. If your sink drain is not the source, check your hot water for rotten egg smells and flush your water heater if necessary.