Looking to integrate a control system that prevents water over flow for a domestic application. I put my idea here in a picture. Can someone suggest me the cheapest way to control the whole system?

Here is the picture...
https://flic.kr/p/51wisN

 

I think you should have one LOW/HIGH volume switch per tank. (empty level/full level)

I would just used a contactor driven by the full level Normally Closed contact in serie with the empty level Normally Open contact.

This repeated for each tank won't cost much.

 

This appears to be a perfect solution for a progammable relay.  They are basically a small PLC with limited abilities and low cost software.  They are available from many sources and I cannot recommend a particular brand.  A-B, Siemens, and Idec among many others sell them.

Bill