Answer
This depends upon where you live
If you are living in Texas area, you may not necessarily have to point your solar heater panel towards south because in this area it is sunny and hot all the year around. So if you are using the solar power as a source of energy for electricity generation it will be no problem.
Find About The Sun
On the other hand if you are living in an area where sun is not there all the time but only at noon then it will be a different scenario. If you are living in northern hemisphere then the sun will be in a southerly direction at its peak. In that case to get the maximum benefit out of your solar water heater you need to face its panel in the direction of sun i.e. south. This will enable your solar panel to receive the maximum amount of sunlight possible. This will enable you to not only run your machinery, but also will save power and money.