Same here. No voice mail left. Have no idea what this call is about

Still calling several times a week with no messages left.

I got a card in the mail with this number on it.  Has *SCAM* written all over it.

The return address is:
CWR
231 W 67th Court
Loveland, CO 80538

Message on the card says:

WATER UPDATE
Unfortunately we have been unable to contact you by phone.  Please contact us within the next 72 hours.  Call between 9:00am - 8:00pm - Monday thru Friday
10:00am - 2pm - Saturday
1-970-292-6186

...and in small print at the bottom:
NOT AFFILIATED WITH LOCAL, STATE OR MUNICIPAL WATER COMPANIES OR HEALTH DEPARTMENT

My wife received the post card in her name or "current resident", we just moved into a home in Windsor.  I did call, and they told me that because of complaints in my neighborhood they do offer free water testing, and only ask that both my wife and I are there together so they can go over the results.  As I was concerned whether this is legitimate or not, I explained I would have to call them back to book a time, etc.  They did not come across as sales push or uncomfortable, but I definitely wanted to research on my own as I had never heard of this before.

We received a card exactly like the one you describe.  I came online to conduct research, see if I could ascertain the reason for the postcard and something about the sender. I'm with you: this has scam written all over it.