Our Recommended HDPE Configuration

The HDPE Rainstopper with Tetherlok combines cost-effective inflow protection with drop-through prevention. The patented Tetherlok cable system secures this lightweight insert to the manhole frame, preventing accidental loss and costly retrievals.

This is what differentiates Rainstopper in the plastic insert space. At only 2 pounds, HDPE inserts are easy to handle but also easy to lose. Tetherlok solves that problem.

Why Tetherlok Matters for HDPE

The nature of plastic means HDPE inserts can easily slip during inspections or be swept down the line. The Tetherlok system addresses this:

• Stops accidental drop-through – If the insert slips, it remains securely tethered and suspended rather than falling through the system.
• Protects against downstream blockages – Insert remains securely tethered, preventing it from being sucked down the line and avoiding costly retrievals that can range from hundreds to thousands of dollars.
• Ensures reinstallation – The manhole cover cannot be closed until the insert is properly reattached after inspection or maintenance.

Need maximum durability for high-groundwater environments? See Stainless Steel Rainstopper with Tetherlok 

Key Benefits

• Cost-effective solution – Lower-cost option with effective inflow reduction performance.
• Tetherlok drop-through prevention – Prevents loss and accidental drop-through.
• Lightweight and easy – Weighs just 2 lbs; quick, one-person installation.
• No engineering needed – Designed for straightforward use with minimal preparation.
• Durable plastic (HDPE) – Resistant to impact, chemicals, oils, and fuels.
• Smart choice for light storm areas – Ideal for municipalities with fewer heavy rainfall events.
• Odor and noise control – Reduces sewage odors, traffic noise, and manhole cover movement.