Why Water Comes Out Black in the Shower After New Plumbing

Manganese Disturbance

• If you are connected to public water and the plumbing was replaced from the main, there’s a possibility that a mineral called manganese was stirred up during the work, causing tiny particles to flow through your water. As the water sits in the pipes, this sediment builds up and will come from your fixtures looking dark gray or black. As the shower is not used as often as the toilet or kitchen sink, the plumbing leading to that fixture might be holding the sediment longer. The shower head might be holding sediment, as well, so taking it off and rinsing it out might help with the problem.

Pipe Disturbance

• If your old plumbing was clogged with mineral deposits, the flow was likely restricted. If new plumbing was installed ahead of the old plumbing, scale buildup that has manganese staining will be broken free by the higher water flow and pulled into the water supply -- likewise if you have any older rubber pipes ahead of the new plumbing. The rubber might be rotting, and the decayed rubber is being flushed through your system.

Charcoal or Carbon Filter

• If your new plumbing included a charcoal or carbon filter installation, particles from the filter were distributed through the water when the system was initially restarted. The shower lines and shower head can hold those particles longer because the fixture is not used as often as other water sources in the home. Removing the shower head and rinsing the particles from the holes can flush the charcoal from the fixture.

Chlorine Reaction

• If you had a chlorinator installed at the time of the new plumbing, the chlorine might be reacting with minerals that naturally exist at low levels in your water. Because the water sits undisturbed in the shower line longer than other water sources, it has time to react, staining the water dark. Be sure your chlorinator is adjusted properly to resolve the problem.

Corrosion

• If copper pipes were linked with other metal pipes in your new plumbing, the two metals might be reacting, causing the copper pipes to corrode. The corrosion turns copper pipes black, and that residue can be distributed into the water supply. Copper pipes also can corrode if introduced to low amounts of electricity.

Other Minerals

• Sulphur in your water could turn it black, but you would notice an unpleasant odor, as well, when running hot water. If the black water also smells like rotten eggs, sulphur has be introduced to your water system and needs to be addressed by a plumber.