My water preasure is 140psi I tried to adjust the regulator but it did not change. Does this mean the regulator is bad.
The reason I ask is I just replaced my the hot water tank the pressure relief valve leaks water after there has been a high demand. The hot water tank has a expansion tank I did check the filling valve to make sure there was no water coming out of it when I press on it to release air it is OK

Hi deacon and welcome, did you make the adjustments with the water turned off? With about a half turn at a time then re-test?
Are you saying you changed your water heater because the pressure relief valve was dripping?

If your water pressure is 140 pounds and you cannot adjust it with the PRV, the PRV is defective. Replace.

I would do the following:

1. Make sure PR is not defective (measure Before and After PR. Reading should give you two different values)
2. Make sure PR is installed with Flow Arrow pointing in the right direction (Arrow marked on body of PR pointing towards the house)
3. Make sure PR is installed on house plumbing system, not on irrigation branch
4. Make sure there is no non-pressure regulated water looped back into the house (like connecting sprinkler pipe in the back into the house plumbing system )

Also, take a water gauge and go around the house measuring pressure at different outlets. Find out which one has reduced pressure and which ones don't.

Last but not the least, read the label on your PR and make sure it says "15-75 psi".

Back to you

Milo