We have had all kinds of issue with the water meter reading too, and getting lot rent invoices in a timely manor.

Water from the well has sediments and water forms a yellow lining in toilet.

New payment is 4150 including taxes and insurance 80 waterHot water bill is 125Rents 8350Very happy with my first BRRRR

Usually if it is something no HoA I solve the issues but now the prolem is under the HoA mercy that seems to careless and the water damages are severe and scary on the photos.

Appears the guests may have left the faucet "on" when the pipes were frozen and when no water came out, forgot to turn it "off".What may have caused the overflow of the sink is maybe the drain lines were also frozen?

Water overflowing the sink, seems more plausible than some missing caulk.  

At one single family house there was an oil haot water boiler with domestic hot water.

Water meter-water company.  

Locate sewer, old septic tanks,  and water lines.  4.  

Quote from @Aaron Wolman: I would call the companies (gas/water/electric) to get estimates, or an estimator out there.