Black build-up on your shower head may be due to a number of different causes. In recent years, it has been reported that shower head build-up may lead to health problems as the particles become airborne and inhaled when the shower is run. At the very least, cleaning your shower head may lead to improved water flow, and you just may improve your health in the process.
Minerals such as calcium and lime can collect inside the individual holes of your shower head. While some evidence of mineral deposits turns white, some can also appear blackish-grey. Areas with hard water are more prone to mineral deposits. Older pipes made of galvanised iron or copper can also leave dark deposits as the pipes corrode naturally over time.
According to the Drains & Plumbing website, municipal pipelines can carry sediments and small debris through the waterways to your shower head, leaving unsightly build-up and reducing water flow.
Mildew thrives in humid places with low air circulation or ventilation. Even if your bathroom has a vent, fan, or window, water droplets can remain trapped in the shower head and allow mildew to grow.
Mold can grow on infrequently used showers (such as those in a guest bathroom). Because some mould is extremely hazardous to humans, it is important to have a professional address any mould problems.
Bacteria and Germs
A shower head that exhibits a slimy, dark green or black build-up may contain Mycobacterium alvium (M-alvium), a germ that is linked to lung disease, according to Professor Norman Pace and other scientists from the University of Colorado at Boulder. M-alvium is closely related to the germ that causes tuberculosis. The bacteria stenotrophomonas maltophilia can also live in shower heads and lead to build-up.