I live in a condo. No place to attach a hose outside. I have a closet on my back patio with the hot water heater. I would like to put a valve where I can attach a hose on the top of the hot water tank. If I could have both hot and cold water that I could mix that would be even better.
Thanks,
Paul Gailey

Any wall mounted laundry faucel will do: Some are here: Laundry Faucet | fixtureuniverse.com

The pipes need to be supported well, so mounting flanges, 3/8 all thread and pipe clamps (Home depot has them) will work nicely.

I'd use a cap on the faucet when not in use.

Hopefully, you don't have troubles with freeziing pipes. A water hammer arrester might help

If you want, you probably could add a ball valve on the end of the spout to have on/off operation after setting the temperature.