Grey Water Harvesting

Need a design for Grey Water Harvesting


I am building a house on 30x40 plot in Bangalore. I have made the provision for storing rain water which is approximately 30,000 liters. I want to harvest the grey water as well. I want to reuse only the water from the kitchen and washing machine. We are a family of 4 including a 3 years old kid. Is it worth considering grey water harvesting? If yes, what is the storage capacity required? What should happen when the grey storage tank overflows? Can someone please send me the design?

Thanks, Shishir Thalner