Background and Aims: In this study we measured the quality, corrosiveness, Ryznar stability index, and heavy metal leakage in the drinking water distribution networks of Ahvaz.

Materials and Methods : A total of 76 sampling sites were selected for this purpose; the sites included inlet and outlet points in water treatment plants as well as consumers taps. We collected 456 samples in six stages and over a period of six month, following the procedures outlined in the Standard Method. Data were analyzed using the SPSS 11.5 software package.

Results: The average values obtained from the specimens were as follows: temperature (19 0C), turbidity (1.97NTU), pH (7.31), pHs (7.88), EC (1678µs/cm), TDS (1006mg/l), Alkalinity (129mg/l), Calcium (109mg/l), DO (6.78mg/l), Cl- (293mg/l), SO4-- (264mg/l), Ryznar stability index (8.43). Average heavy metal levels in tap water were as follows: Pb (8.48µg/l), Cd (0.972 µg/l), Zn (3.18 mg/l), Cu (0.168 g/l), Fe (0.257 mg/l), and Mn (0.031mg/l).

Conclusion: The results showed that the water quality has been affected in such a way as to cause corrosiveness, heavy metal leakage and aesthetic problems. We also showed that in comparison with USEPA and Iranian standards, the quality indices of the drinking water in Ahvaz were at an acceptable level, with the notable exception of a few indices such as TDS, EC, and hardness. The Ryznar stability index indicated that the drinking water in Ahvaz has corrosive properties and this could be one of the reasons behind the high rates of heavy metal leakage detected in this area.