PSI and Verification Unit

This is the most expensive confusion in the whole process. Hiring one company for both looks efficient and produces a report that is worthless.

What a Verification Unit does

It attests and verifies. Its work is to visually attest and verify that the metering system and everything around it satisfy the standard, and to put the outcome in writing in a report. Nothing else — and that is precisely the point. ¹

What it is forbidden to do

CONAGUA approval requires the Verification Unit to abstain from supplying meters or metering systems, from installing, repairing or maintaining measuring instruments, and from transmitting measurement data. ¹

This is not a commercial preference or an internal policy: it is a condition of approval, and breaking it puts that approval at risk. A unit that sold and installed the equipment it later rules on would be assessing its own work.

What a service provider does

The service provider does exactly what the unit may not: supplies the equipment, installs it, repairs it, maintains it and transmits the data. Both roles are necessary and neither replaces the other. What cannot happen is for one company to play both for the same water use.

Why independence is the requirement, not a flourish

A verification unit is accredited against the requirements for the operation of bodies performing inspection, and impartiality is the first of them. A report carries weight because whoever signs it has no stake in its outcome. ²

How to check before hiring

Before starting the process, the unit must exhibit the documents evidencing its current accreditation and approval, the names and photographs of its verifying personnel, the names of any assistants taking part, and the applicable fee. If any of that is missing, take it as a warning. ¹