How much maximum water can pass from a 1/2" hole in 1 hour?

Question

How much maximum water can pass from a 1/2" hole in 1 hour? pressure is 145 psi.

Answer 1

Look at the link, the flow depends on the geometry of the orifice (hole).

The link gives:
Q=19.63*d^2*K*sqrt(H)
Q in gallons per minute
d is hole diameter in inches
K is a flow coefficient - between ~0.5 and 1.55 (so flow varies by a factor of 3 depending on the shape of the hole)
H is the head in feet
Head = psi/0.434
There are 60 minutes in an hour

you do the math.