Is this water heater drain configuration safe?
The configuration you pictured is not really a good idea. Waste water from the washer is going to flood the heater drain pipe, leaving nasty residues that could conceivably siphon back into the heater if connected to the heater drain valve. Not likely, but possible any time two drains are connected at different levels other than directly into the vented out flow pipe. The other problem will be that if the drain is a open pan drain only, washer waste water will back up into the pan. Washers tend to eject water quickly and can partially fill the pipe above the trap.  

I would rather see you pump it up to the inlet of the washer drain.