Item 1Water heater relief line, vent joints and expansion tank support
Observed. A Rheem PowerVent 2 gas water heater stands in a closet. Two seismic straps are installed. The relief valve line leaves the top of the tank in copper and turns down the wall in white plastic pipe. A second white pipe on the same wall is printed ASTM D1785, the standard for PVC pipe. The expansion tank hangs from the water piping with no separate support. The vent changes from black to white plastic fittings below the ceiling, with dark staining at the upper fitting.
Why it may matter. The relief line carries scalding water if the valve opens. The plumbing code requires its material to be rated for the system temperature. PVC is generally limited to about 140°F. A full expansion tank is heavy. The manufacturer's instructions govern how it is supported and how the vent is joined.
Typical correction. Replacing any discharge pipe not rated for the temperature, supporting the expansion tank and correcting vent joints as the instructions require.
Suggested next step. Have a licensed plumber review the relief line, the expansion tank and the vent before your contingency period ends. Ask the seller for the installation date and the permit.