Pinellas County's water department has issued a warning advising residents to beware of companies offering free water tests.
One elderly couple said that test led them to make a $2,000 mistake.
The post card offered Donald Dennis and his wife a free water test. What the Seminole couple did not know is Pinellas County Water and Sewer routinely monitors the water supply for contaminants.
Bob Powell, director of Pinellas County Water and Sewer, says there were no violations in the 2011 report.
But the Dennises claim the company that checked their water never mentioned the county's water test results.
By the end of the sales pitch, the Dennises, both of whom are in their 80s, believed they needed a $2,000 water-treatment system to protect them from contaminants.
Donald doesn't remember signing a paper that states the company never said the water was harmful in any way.
Still, stories like the Dennises prompted Pinellas County to issue a warning about companies that use scare tactics to sell a water treatment product.