These results correspond to analysis of the first morning water collected at the sink. Values for iron content are several times the values corresponding to water from the aqueduct. It is evident that rust from the pipes comes mixed in the first morning water.

Rust advance inside the pipes is more severe than one would imagine. After continued use for more than 15 years, lumps of rust appear at piping joints, and deposits of red rust are created.

The inside of pipes is made of iron, whereas copper is used at water meters and valves. Because of this, the combination of two different metals results in localized fast corrosion of the weaker metal. This type of corrosion is called "Galvanic corosion".