Do water heaters have a check valve?

[jbr383]

I recently teed into the cold water supply line that goes to my water heater. I planned on supplying another fixture in the garage through this tee. I started wondering, because the tee is so close to the inlet to the hot water heater, when I open up the new fixture will it draw hot water back out of the tank?

[jadnashua]

It's not likley...

[hj]

NO, but the water in the line above the tank will usually get hot because of convection, so the initial water, at least, will probably be hot.

[jbr383]

Thanks HJ. I kind of figured/hoped the water was just getting warm from convection.