There are places even away from Athens where there is clean water problem because of the pipe, and chlorine often in large quantities.

Good thing is to avoid plastic water pipes of PVC, which contain chlorine and other ingredients, convenient for manufacturers, but not necessarily for tenants. Currently considered the best choice copper tubes, but raise by 15% the cost of a new hydraulic system.
Also important is the positioning of a good filter carbon in order to letting pass 97% of the beneficial ingredients (calcium, potassium, sodium, magnesium), and harmful to the respective decreases by over 97%. Finally, bind the chlorine sizable percentage from the start of the water path inside the house.