If no permit I would discharge into a 30 gallon steel container with a hole in the lid. I have never had a run away electric water heater in all my years, and most drips are just bad valves. For that matter you could set another "open" water heater next to it and discharge into the cold inlet. I see 40 gallon rigs for $199 now, and thats the cost of a few good garbage cans.
That also gives you your next water heater ready to go.
Running a pipe is a better idea, of course. And legal, if you care.