To find the change in the amount of water in gallons in 1 minute, we start with the rate at which the pump removes water.
The pump removes 250 gallons of water in 5 minutes.
To find the rate in gallons per minute, we can divide the total gallons removed by the time in minutes:
\[ \text{Rate} = \frac{250 \text{ gallons}}{5 \text{ minutes}} = 50 \text{ gallons per minute} \]
Since the pump is removing water, the change in the amount of water is negative. Thus, the change in the amount of water in 1 minute is:
\[ \text{Change} = -50 \text{ gallons} \]
The answer is \(-50\) gallons.