No, you need high density. Look for pink.
Pink is high density. It's just a higher grade for use on water lines. Unless you're working on something major or under higher pressures the white will probably work just as good for you.
sure, this is no problem. ptfe tapes with anti- high pressure. http://ptfe-tape.com
I'm not a plumber, but here is my thought: If the leak is coming from a threaded fitting to or from the heater, you could use it. But that's not likely. Usually when a water heater leaks it's from something inside the heater, mostly a damaged trank. Or maybe corrosion. Regardless, the tank then has to be replaced. Of course if it's under warranty, you should contact the installer.
No, use yellow.
No, use yellow.
If the carton packing shows manufacture date, it is better. But PTFE tape manufacture date is not important . http://ptfe-tape.com
Yes! Just follow directions.
260 inches of 1/2 in tape is wound around the spool. Also sold is multiple rolls in one package.
You cannot order a case.