Can a high water damage my water heater?

Of course, if its high enough as will it the pumbing etc... the question is how high is it actually right now.

To add to Smoothys questions. Well or city water> And if on the city do you have a PRV (pressure reducing valve? If the PSI is too high the T&P valve on 6the heater will open up and save the heater, however Smoothy's correct. High water can, and will, damage your faucets and put your pipes and fittings under a strain. Answer smoothy, what's your house PSI? Back to you, Tom