I live in Colorado, USA. All gas stations must have shallow wells drilled around the gasoline tanks to monitor for gasoline tank rupture leaks. The tanks usually lie above the water table so any gas leaks will travel to the water table and start flowing on top of the groundwater. One hundred percent contamination happens when a flashlight is shined down the well and a gasoline sheen is seen on the water. Less contamination is measured by sampling the water. The depth to the water table is also measured.
The point I am getting to, is that all gas stations in Colorado have to be measured every three months and the results sent to the State. I would suggest that you check for a gas station near where you live and get a recent published water report that you can study. One of the maps is a water table depth map. The map will have a contour map with the depth below surface contours and arrows perpendicular to contour lines that show the direction of groundwater flow.
I would suggest for you to see if your State or Provence has a similar contamination monitoring program. This would give you an idea how the water table behaves in your area. If you go to your nearest gas station and look for circular steel plates about 6 inches in diameter placed flush on the ground around the tanks, gas pumps, and parking lot, then you will know if the station is monitored. The top of the plate has a filled in triangle with the triangle points touching the circle circumference. Sometimes the plate has a warning that says "DO NOT FILL". The the steel plate and map symbol looks like Unicode symbol U1F7D5.