Class 125 PVC Caps

Maxx Supply’s Class 125 PVC caps are precision-engineered to seal the ends of PVC piping systems efficiently and affordably. Designed to meet ANSI Class 125 standards (~125 psi at 73 °F), these caps are compatible with both Schedule 40 and Schedule 80 PVC pipe systems.

Each cap delivers a secure, corrosion-resistant seal that’s ideal for temporary or permanent closures. Whether you're sealing irrigation lines or plumbing systems, Maxx Supply caps offer an economical, reliable solution for a wide range of applications.

Suitability & Applications

Class 125 caps are used in pipe systems that operate under low to moderate pressure and temperature conditions. These fittings are ideally suited for:

  • Potable water systems
  • Agricultural irrigation
  • Stormwater drainage
  • Light industrial and HVAC piping
  • Pool and spa plumbing services

Rated for use in environments up to 140 °F, these fittings perform reliably across seasonal and long-term applications. Their durable, lightweight construction makes them easy to handle on jobsites and resilient against corrosion, even in high-humidity environments.

Sizing Guidance & Compatibility

Choosing the right cap size starts with understanding your system’s pipe fitting dimensions. Maxx Supply’s Class 125 caps are sized according to nominal pipe dimensions, meaning the cap’s socket fits over the pipe’s outside diameter.

Here’s what to consider:

  • Match the cap’s size to your pipe’s nominal diameter (not inner diameter).
  • These fittings are designed for both Schedule 40 and Schedule 80 PVC, though wall thickness will affect total fitting depth.
  • Ensure clean cuts, proper alignment, and tolerance awareness for a reliable seal.

Proper fitting ensures leak-free performance, so taking time to prep your pipe ends can make all the difference.

Installation Best Practices

For optimal performance and safety, follow these steps:

  • Clean and deburr: Wipe down the pipe and remove all debris from the surface and edges.
  • Dry-fit: Confirm proper sizing before applying solvent.
  • Prime and cement: Use primer followed by PVC cement (especially for pressure systems) to create a secure bond.
  • Twist into place: Insert the cap with a quarter-turn motion and hold for 30 seconds.
  • Cure and test: Allow appropriate curing time, then pressure-test the system per the manufacturer's guidelines.

This process reduces the risk of backflow, pressure blowouts, or long-term leaks — and supports maximum performance over time.

Common Use Cases

From contractors to DIYers, Class 125 caps are trusted in a wide range of field conditions:

  • Temporary sealing during new system installations or flushing operations
  • Seasonal closures, such as winterizing sprinkler lines or draining pools
  • End-of-line caps in lab, irrigation, and vacuum systems
  • Testing and inspection stages in chemical and water treatment processes

These fittings provide dependable seals where ongoing maintenance or system expansion is planned — delivering flexible solutions without compromising safety or efficiency.

Why Choose Class 125 Caps from Maxx Supply?

Built to balance durability, safety, and affordability, these caps are ideal for everyday plumbing and specialty work alike:

  • ANSI Class 125 rated for 125 psi at 73 °F
  • Engineered for use in Schedule 40/80 systems
  • Lightweight and resistant to corrosion
  • Easy to install using common tools
  • Available in multiple sizes with reliable availability
  • Designed for a variety of low-pressure applications

Maxx Supply carries a full inventory of Class 125 fittings, including elbows, tees, valves, and more to round out your project. Browse our Class 125 fittings page to find the components you need with trusted availability and expert support. Whether you're capping a run or customizing a system layout, we have the fittings to match.