what would be the height of a water barometer if atmospheric pressure is 1.0*10^5 Pa and the density of water is 1.0*10^3 kg/m^3? (Hint. Use p= 10 hd)

p = rho g h

10^5 = 10^3 * 9.81 * h

h = 10^2/9.81

You seem to be using 10, not 9.81 for g so

h = 100/10 = 10 meters

That is about 33 feet which divers figure is about one atmosphere gage.