– why doesn’t the water in our pipes get bacteria/viruses in it?

Question

It seems like you would get pretty nasty germs happily living in our plumbing (especially untreated well water).

I think about the water that can sit for prolonged periods in hot water tanks, stagnant water in dead end sections of the plumbing system (unused outside faucet etc), and the wet oxygen rich environment inside the faucet ends.

Yet you almost never hear about people getting sick from their water🤷🏽‍♂️

In: 1670

Answer 1

There are three reasons.

First it’s highly filtered so there’s a lack of nutrients that bacteria can use to grow. In general the filtration process is sufficient to remove very nearly all bacteria amd other single celled organisms, but not all viruses which tends to be exceptionally small. Any bacteria that do manage to escape can’t grow because there’s no food source.

Second, water utilities add chlorine (Cl2) or certain chlorine compounds like ClO2, Chloramine, or Ca(OCl)2 which are toxic to single celled organisms, but not to humans because we have means to detoxify the chlorination. Point of fact immune cells in your nose and lungs produce Hypochlorite ions (OCl-) and superoxide ions in response to coming in contact with foreign particles, in order to kill and inactive them. So chlorination is really just humans learning to take advantage of a chemical defense strategy that living things have been using for hundreds of millions of years. Various mucous membranes in your respiratory tract have an epidermal layer composed of dead cells which protect the underlying tissue from insults like reactive oxygen ir chlorine compounds or food acids, excess salt, alchohol, etc.

This also quickly destroys or inactivates viruses. Viruses are wholly parasitic and can’t survive very long outside their hosts.

Third, potable water pipes are usually made of copper. Copper is also toxic to almost all life forms except in tiny amounts. This prevents bacteria or other organisms from growing on the inside of pipes in the event that the water treatment facilities break down and some biological contamination enters the water. Water mains pipes are often PVC plastic that has several percent of certain copper compounds added to the plastic, for the same reason. This gives them a green or bluish green color. However copper doesn’t dissolve much in water and traces of copper in potable water aren’t generally absorbed by the digestive system.