This does not lessen the need to use qualified plumbers. Be sure they use quality material and follow generally accepted practices. The Uniform Plumbing Code seems to me to be the industry standard for this information. It also states that temperature and pressure-relief valves shall be vented outside of the building. Be advised that it is risky business not to turn water off at the meter when leaving for any length of time.
Some people even turn the water off at the meter when they are leaving just for the weekend.
Even a small leak unattended over time can cause extensive property damage. You have to decide what degree of exposure you are willing to accept. For those who are using the drop box in our door, please be careful to put your payment all the way into the box. It would also help if the card was either stapled or paper clipped to the check. Sometimes we have a lot of mail in the box and it is hard to match up the check with the card.