An open ground means that you don't have a dedicated path to ground. Your tester just verifies that there is a return path for the current, but it could be via the neutral wire in the circuit.

It's tough to tell the difference between a neutral and a ground without inspecting the wiring itself, since they are both typically connected to same place in the breaker box. The difference is that the ground is only used for safety purposes, while the neutral is used to close the circuit under normal operation.

"Isn't that an indication of grounding?"

It means the screw is likely grounded.

It does not mean a ground is connected to the receptacle.

It could be as simple as the wire coming off the ground screw on the receptacle, or the cable ground being connected to the box (possibly through an armor jacket) but that the actual receptacle grounding screw not being hooked to anything.

Home inspectors sometimes know just enough about electrical wiring to be dangerously wrong.

Very true bus_driver. A few years ago a friend was selling his house and the home inspector said that each outlet in the master bathroom had to be GFIs . These were on the same circuit and one fed from the other. This was pointed out to the inspector but he insisted he was correct and both had to be an actual gfi. He also said even if a gfi breaker was installed they would have to be gfi outlets "because all outlets in a bathroom must be gfi". In the end it was easier to install 2 GFIs rather than get him to see the error of his decision.

> The Home Inspector said I have an open ground, but when I touch
> one leg of my very basic electrical tester to the outlet ...

First, which ground? You have at least two electrically different grounds. Which is open?

Second, a tester cannot report a good ground. It can only report some failures. And only for a safety ground. The tester says nothing about earth ground.

Again, that tester can only report some failures. Cannot report anything any ground as good. Grounding must always be confirmed by visual inspection.

"Grounding must always be confirmed by visual inspection. "

Ground testers (low voltage until the desired current is reached based on the circuit rating) have been around for many years now.

The earth connection of the service is not the issue here.

The safety (groundING) conductor is.