u/PK_Chewy

I just got a Belgard paver patio & walkway installed 2 months ago. Now, I see rust spots in various location on the patio, on the walkway to the front as well. I have the installers coming out to look. I have an irrigation system but the entire neighborhood has as well and we all get water from the local ponds and nobody has my issue. My furniture is non- metal, my grill is on a mat- under the that mat there's no rust. No tools or metal are left on pavers. It was completed in 1st of August. What can it be? Any help is appreciated.