Standard PVC pipe begins to soften at around 176°F (80°C) and can fully melt once it reaches roughly 250°F (121°C) — well above what most household hot water systems produce, but worth knowing if pipes run near a heat source. CPVC (chlorinated PVC), which is rated for hotter applications, has a higher melting point and a higher continuous temperature rating than standard PVC, which is why it’s used for hot water lines where standard PVC isn’t allowed.
For reference, PVC’s typical continuous temperature rating tops out around 140°F (60°C) — that’s the practical temperature limit for pressurized use, even though the pipe itself doesn’t start to deform until well above that. On the cold end, freezing temperatures aren’t a melting concern but can still crack PVC piping under freeze expansion, so both heat and freeze exposure are worth avoiding. If you’re not sure whether PVC, CPVC, or another material is right for a hot water or high-heat application, The 5 Star Plumbing can advise on the right pipe for the job.