In my house I measured about 3 Amps in ground wire from 100 Amp electrical panel.
We are consuming about 1200 KWh monthly.
Is that normal for 850 sq ft house and family of four?

Nope, doesn't seem right.

Your getting 3*120*24*30/1000 or about 259 kwh from that ground current.

You didn't mention the conditions and what type of stove, water heater or furnace you have, but the numbers don't seem right.

You didn't mention how measured (clamp on meter) and the accuracy and resolution.

At $0.12/kwh that's about $32 too much. I'd ask you neighbors/

Any voltage on ground isn't good. If you have copper pipes and a clamp on ammeter, put the meter around the copper pipe and see what you get.

Thanks for the prompt response.
Appliances are all few years old (all electric, except furnace) as well as new 100Amp panel.
It was measured with borrowed Greenlee CM-800 600A AC Clamp Meter.
Some copper pipes are 0.1 but one is 0.6.

Oh, no my neighbours are not paying even close what we're paying... :-(
What should I do?

Please help!

If you used that meter http://www.mygreenlee.com/GreenleeDotCom/im/99947536rev02.pdf

and measured the ground rod current,

the error bars on the 600 A scale, your looking at 1.9%(3) * + 0.7 so the error is about 0.75 A

So, 3A seems too high.

At this point, I would call the power company and ask them to check your service because you measured what you think are excessive currents within the meter accuracy on the water pipe into the house and the ground rod. Can you have someone come out and verify. I have additional measurements that I can give you now.

And go from there. At this point the copper pipes are within the error limits of zero. The one of interest is the pipe as it enters the house or basically before it's buried the first time (could be under slab).

Additional things you can do is see if there is any significant difference when you turn off all, one or some of the breakers including the main. If it's a single circuit or a few circuits, call an electrician.

Best suggestion I can come up with.

1. You used a CM-800 clamp meter on the x scale which has an accuracy of x%+yA.

2. You looked at the current on ground rod and it was ___+- y amps (compute error).

3. You looked at the current on the water pipe bond and it was __ +- (compute error again)

4. You looked at the current on the water main just as it entered the house at ____+- (compute error)

5. The line to ground voltages were ____ and ____ (expect 120)

6. The line to line voltage was (expect 240)

Having 3 amps on a grounding electrode conductor is not a serious condition, thou should not be there.

Current flowing on this conductor will not affect your electric bill. Your bill is due to your electric usage.

Kiss offered good advice, to shut off your Main Breaker and take a measurement to confirm if the current is coming from your system, as the current may or may not be coming from your system.

Grounding Electrode Conductors (http://ecmweb.com/grounding/electric_shocking_truth_grounding/)