The results of the present work have shown that acrylic (AA) and maleic acid (MA) homopolymers are effective inhibitors for the formation of gypsum and calcium carbonate scale deposits. Both the presence of functional groups and the MW of the polymers played a significant role. The presence of freely ionizable, sterically less inhibited carboxyl groups showed higher inhibitory efficiency. The MW of the polymers tested did not affect significantly their anti-scaling efficiency. However, higher efficiency was obtained for the lower MW polymers, a fact attributed to the stronger interaction with the surface of the calcareous deposits. At the same time, the polymers tested, both homo- and copolymers showed satisfactory dispersion ability for iron oxide particles, with the exception of molecules lacking functional groups which may be ionized. The efficiency of the polymers tested with respect to the dispersion of iron oxide particles increased with concentration and time. Finally the tolerance of the AA and MA polymers towards calcium ions in the solutions was minimal. Copolymers in which pyrrole and sulfonate or amido functional groups were included, showed very good tolerance towards calcium in solution, irrespective of their MW. Apparently, it is the presence of the functional groups tested that is responsible for the increase of tolerance towards calcium.