Since your water sensor is non-alarm, I don't think you can require entry of a keypad code to clear the message. The condition will clear when the water sensor dries out. Until then, you could bypass the zone.
If you are using the water sensor to trigger a water shutoff valve, how will you open the valve again? Manually? Via an F-key press and a rule to open it? If you bypass the water sensor zone, do you want the valve to open again or stay closed? You can make it work however you want, but it requires some thought on all the possibilities.