The Buyers purchased the property, moved onto the property, and soon learned that the property had an extensive flooding history which they alleged was not disclosed to them. (nar.realtor)
Local council information: This could include flood histories of your local area, evidence of soil drainage in your area, water flow paths, maps showing the location of watercourses and stormwater drains in your area, council commissioned hydrology reports, contour maps etc.. (insurancelaw.org.au)
Flood insurance helps more: Check out your state's flood history with FEMA's interactive data Visualization Tool. (fema.gov)