It's a shame I can't fix anything around the house. I appreciate all the contributors here and have learned a lot reading these forums. Thanks to everyone for their input.
the water is dripping consistently and it is warm. It is coming right from where the screw is going into the black thing.
A pipe comes out of the wall, down to this black thing then out the bottom and back into the wall.
This is in the hot water heater closet it in my garage. The drip is pretty steady but I don't see my water meter moving so i am not sure where the water is coming from, where it is going or most importantly how to fix it.
My assumption is some sort of washer or seal is malfunctioning inside the black thing.
I guess my question is getting into that black thing something I can tackle by myself and where would the water valve be to turn the water off? If I can't - should I call a plumber or someone else?
The valve you show behind the tag is a ball valve and rarely leak, Even if it drips a bit you'll be fine. Besides you will still have water draining back from the plumbing above, expect to get a bit wet.
Shut the ball valve below the PRV, open up 2 faucets on an above floor and one where the leaking valve is. (if there is one). Open an outside hose valve let drain for a few minutes.
Get a bucket and loosen one of the nuts on the pressure reducing valve and let drain for a few minutes. Loosen the other and remove the PRV (pressure reducing valve). NOTE which way the arrow is facing on existing valve. Under the PRV nuts will be "O" rings. Try not to damage them just in case you mangle the new ones. Insert the new valve with the arrow in the same direction with "O" rings and tighten. Shut valves and turn the water back on and check for leaks.
thanks for all the help - I ended up calling a plumber who was a friend of a friend. He needed a blow torch to get it off so there is zero chance I could of done this myself but I learned a lot in the process.