Water testing for house

Good morning,
My water test came back with E.coli. / unsafe.
Yet my two other condo neighbor's test came back negative/ safe.
All water from the same source in the building.
Maybe a false positive?

I would like to know of several testing labs in Z?
I want to re-test with several labs.

Any recommendations?
Thanks everyone!

Besides the ones already listed here on my website?
https://www.zihuatanejo.net/healthmedical.html#laboratories