Where to fix piping to prevent Backflow?

Hi all:

We are ice manufacturer, raw material is water. Recently, we received commentes from auditor said there is no way to sub-connect the piping out (for other purpose usage) in between our water meter and water tank, as this will caused back flow . Below is our raw water flow, i was wondering if i would like to fix new piping for cleaning purpose, where shuold i fix the piping in order to prevent back flow occured? Thanks in advance.


Water Meter - raw water tank - sand filter - water tank - ice maker - finished product

I do not know if I understand this correctly ; but all you need is a back flow preventer valve (check valve) that allows the flow only on one direction
such as this or maybe this
I assume you want it between the water meter and the raw water tank, thus a check valve should be enough as you do not need sanitary valve.
if so I would connect as follows:
Water Meter T [check valve ->] raw water tank - sand filter - water tank - ice maker - finished product
other line

Otherwise, between sand filter and water tank; you may need a sanitatry valve though:
Water Meter - raw water tank - sand filter T [back flow preventer valve ->] water tank - ice maker - finished product
other line

Hi all:

We are ice manufacturer, raw material is water. Recently, we received commentes from auditor said there is no way to sub-connect the piping out (for other purpose usage) in between our water meter and water tank, as this will caused back flow . Below is our raw water flow, i was wondering if i would like to fix new piping for cleaning purpose, where shuold i fix the piping in order to prevent back flow occured? Thanks in advance.
Water Meter - raw water tank - sand filter - water tank - ice maker - finished product