New TDS Meter - reading of 21 from Calgary Water?

[wayner]

Emily:

Then I guess my new TDS meter needs to be calibrated?, I live in the S.E., from what you've posted, I doubt very much that I should get a reading of 21 coming out of he tap. it seems it should be a lot higher?

Now I'm wondering about my RO/Di water.

So would you say a reading of 21 is just about impossible?

Thanks for the info.