Both PVC and UPVC serve different functions due to these differences:
Durability
Because it is designed to be softer and more flexible than many other plastics, PVC is less durable than UPVC. However, both plastics are resistant to sunlight, oxidation, and a variety of chemicals.
Properties
In terms of their properties, PVC contains both BPA and phthalates, which are two plasticizers that make it more flexible. While, the "u" in UPVC stands for "unplasticized," and because it does not have these extra materials, UPVC is often called rigid plastic.
Applications
In most of the times, UPVC is used more widely for water pipes than PVC. The extra materials give UPVC superior resistance to chemical erosion, and its smooth inner walls allow water to flow more smoothly with less turbulence. UPVC is also resistant to a wider range of temperatures than PVC.
While, on the other hand, PVC is the plastic of choice for sewer pipes and the transportation of non-potable water.