Heating water for domestic purpose is a simple and effective way of utilizing solar energy. Initial cost of solar water heating system is high. But we get zero green energy cost. This paper discusses the improving of the performance of a flat plate solar energy collector by changing the design parameters of the number of riser tubes and the arrangement of riser tubes in zig-zag pattern from the existing flat plat collector system. Experiments were conducted using copper tube in header and riser with different dimensions. The performance shows that the efficiency is 59.09% when increasing the number of riser tubes and its 62.90% in the zig-zag arrangement (Z- Configuration) of the riser tube. Now-a-days this system produces higher efficiency than the existing conventional flat plate collector.