The aim of this research was to study the effects on streams water quality of non-point contamination as agriculture and cattle farming activities at a basin with pampean characteristics located at the upper Reconquista River Basin. Eight reaches with different uses in their neighboring zones were selected with the proposed to detect differences at the water quality among them. SRP range was 0-0.60 mgP.PO (4) (-3) /L, ammonia 1-137.3 μgN-NH4(+)/L and nitrate 0-4.15 mgN-NO(3) (-)/L. There was high similitude and homogeneous physicochemical characteristics at the different reaches of the streams. The high levels of dissolved nutrients showed similar eutrophication conditions at the streams.