Using TOC for purified water validation

We are just about to begin a purified water system validation. We are planning on running one months worth of sampling every point of use as well as points in between each component on our skids (IE, between RO, softener, EDI). This is my question. We are planning on having all ports tested for TOC, conductivity, and microorganisms. Is it necessary to test each port for TOC and conductivity? I don’t know if I see reasoning in testing the incoming potable water, the water following the water softener or following the carbon beds. Would in not be sufficient to do TOC testing on everything following the EDI and all point of use ports? Any response would be great, thanks!

No it is not necssory to check TOC and coductivity at each point of treatment / skid. TOC and coductivity reduction is our final acceptance criteria and it is acheved once the water passes through RO EDI, so there is not point is checking these parameters. But offcourse water need to be tested at each treatment point in the skid to ensure that every step of treatment is working. Selection of the tests should be purly base on component in the skid. Hope this is clear…

What type of tesing have others traditionally done during a validation to ensure that each component of the skid is working?