Hi Carine,
There are no standard temperatures for pH measurement.
I can see that your purpose is to ensure the neutrality of your water, neither sour nor basic. Since you outsource a professional lab, you can ask them for water-neutrality test reports including:
- Temperature of the water sample.
- Recorded pH of the water sample.
- Neutral pH of water at the above temperature (e.g. from chemistry handbooks) or the measured pH of the lab's reference pure water in the same measuring condition.
- Definition of the acceptable range = "neutral/reference pH" +/- 1.0, (or 0.5 or 1.5, based on your own requirements)
- Conclusion of the (non)conformity of tested water sample against the acceptance pH range.
Regards.