How to size up water pump for residential area usage?

I need to size up the size and capacity of a water pump for a residential area. I know i need the appliances inside the area (like to wash basin, water closet etc) , the corresponding loading unit and the number of fixtures. But I'm not sure how to get the corresponding flow rate. Can anyone advise me on how to do this. ThanksHow to size up water pump for residential area usage?Im sure if you contact (email/phone) a pump or even a boiler manufacturer they would have the figures you need, or at least point you in the right direction. Im sure they'd do it for free, better for business..