Pressure = (density)(g)(h) where h = the depth of the fluid. The density of water is 1000 kg / m3
The acceleration of gravity is 9.81 m/s2.
. h in this problem is 0.5 m. Multiply alll of these to get 4905 N/m2
or 4905 Pascals or 4.905 KiloPascals. If you want to convert this to other pressure units, 101.3 kPa = 1 atmosphere = 760 mm of mercury.