Why Sediment Control at the Structure Matters

On active construction sites, sediment movement is expected.

Mud tracks across pavement. Concrete splatter happens. Fine particles move with runoff.

But when that material enters a municipal manhole or stormwater structure, it becomes more than a housekeeping issue.

On sites disturbing over an acre, stormwater permits require protecting inlets and drainage structures and keeping sediment out of the system. Most projects already implement perimeter Best Management Practices such as:

• Silt fence
• Wattles
• Stabilized entrances
• Inlet protection

Those measures do a lot.

However, during active construction, sediment and fine particles can still track or seep into manholes and stormwater structures, even with the cover in place. When lids are temporarily removed for inspections, tie-ins, or grade adjustments, the risk increases.

When sediment enters the structure, it can lead to:

• Permit concerns during inspection
• Increased municipal maintenance and cleaning costs
• Reduced hydraulic capacity in the collection system

Preventing debris from entering the system in the first place is often simpler than removing it later.

Adding Protection at the Manhole Itself

Manhole inserts add protection directly beneath the cover. They help prevent construction debris and unwanted water from entering the collection system through the lid.

Rainstopper manufactures stainless steel manhole inserts used in municipal sewer manholes to control water entry through the cover. The same stainless steel insert used for inflow control can also provide protection during active construction.

This approach does not replace perimeter BMPs. It complements them by adding a practical barrier at the manhole itself, where sediment can enter the system.

Simple concept.
Practical application.

If you’re working on a project where manholes are exposed during construction and want to reduce risk at the source, we’re happy to have a conversation.
Contact us anytime. We’re glad to help.

Phone: 318-667-4330
Email: Info@rainstoppercompany.com

The Challenge

When Hurricane Sandy made landfall in 2012, New York City’s underground infrastructure was severely impacted. Treatment plants shut down. Underground utilities were flooded. Recovery extended for months.

In the aftermath, the Metropolitan Transit Authority sought cost-effective ways to prevent floodwater from entering access structures and underground vaults.

The objective was straightforward:

Protect existing infrastructure without rebuilding it.

Identifying the Gaps

Structure inserts were identified as a promising mitigation strategy. However, existing products did not meet the complexity of New York’s infrastructure.

Challenges included:

• Diverse frame shapes and sizes
• Protruding locking lugs
• Drop rings requiring tight tolerance
• Oversized 48-inch openings
• The need for gas monitoring without removing inserts

No single product addressed all conditions.

Engineering the Solution

Rainstopper worked with contractors including Zafra Minhas Construction and WBE Dorcas Inc. to develop five new insert designs:

• Stainless steel insert with extended lip and angled drop
• Square insert for ConEd electric utility structures
• Extended-life elastomeric gasket for long-term durability
• Large-diameter 48-inch insert
• Insert featuring an external gas detection port

All products passed third-party certified hydrostatic testing at 16 feet of water head. Units exceeded the 1,000-hour requirement, with some operating beyond 2,500 hours under sustained pressure.

More than 250 units were manufactured and installed following detailed on-site measurement training to ensure proper fit.

Results

• Standard specification approval with the MTA
• Installation across all five boroughs
• Floodwater prevention in parking lots, roadways, and utility structures
• Reduced inflow and infiltration into treatment systems
• No major infrastructure modification required

Ongoing Relevance

Flood protection systems must perform under pressure.
They must install efficiently.
They must work within existing infrastructure.

The inserts developed for the MTA remain in service and continue to support flood mitigation efforts across New York.

We didn’t approach this as a product exercise.
We approached it as a problem to solve.

Keep the water out.
Protect the infrastructure already in place.
Build solutions that work in the real world.

That’s how we approached New York then.
It’s how we approach flood mitigation today.

Questions about flood mitigation?

Phone: 318-667-4330
Email: Info@rainstoppercompany.com

In the real world, manholes rarely match the drawings perfectly.

Frames are off by a fraction. Covers have been replaced over time. Drop rings show up where no one expected them. Field crews are left figuring out how to make a standard product work in a non-standard situation.

That’s where customization matters.

At Rainstopper, customization isn’t a special program or an upsell. It’s simply how we’ve worked for decades. Our inserts are designed to solve inflow problems in real systems, not ideal ones. That means being able to adjust, modify, and build to fit what’s actually in the ground.

Why Customization Exists at All

Most inflow issues don’t come from a lack of products. They come from small mismatches that turn into big problems over time. A gasket that doesn’t seal quite right. A handle that doesn’t hold up in a harsh environment. An insert that fits on paper but not in the field.

Customization addresses those issues before installation, not after. Sometimes that means choosing a different material. Sometimes it means upgrading a gasket. Sometimes it’s as simple as welding a handle instead of riveting it. These are not complicated changes, but they make a measurable difference in performance, longevity, and ease of maintenance.

Built From Experience, Not Theory

Rainstopper has spent more than 50 years working directly with municipalities, engineers, contractors, and operators. Because everything is built in-house, adjustments don’t have to go through layers of approval or long redesign cycles. When a project calls for something slightly different, it can usually be handled quickly and clearly.

The goal is not to reinvent the product, but to make sure it works as intended once it’s installed. This practical approach is also why Rainstopper holds multiple U.S. patents. Those designs came from solving repeated field problems, not from adding complexity for its own sake.

Common Customization Decisions

Most customization conversations start with a few straightforward choices:

Material Selection
304 stainless steel works well for most municipal applications. In higher-corrosion environments like coastal regions or areas with heavy road salt use, 316 stainless steel is the better option.

Gasket Selection
The standard neoprene gasket performs well in typical conditions. For flood-prone or high-groundwater areas, the extended-life gasket provides added assurance and long-term stability.

Handle Options
Nylon handles are lightweight and corrosion-resistant. Stainless steel handles offer added durability. Welded handles are available when maximum strength and zero failure points are required.

Security and Retention
In areas where theft, loss, or accidental drop-through is a concern, adding the Tetherlok system prevents downstream blockages and costly retrievals. For HDPE inserts in particular, this is an important consideration.

None of these decisions are complicated on their own. What matters is choosing them intentionally, based on how the system will actually be used.

Measurement Still Comes First

No amount of customization helps if the measurements are off. Accurate frame and cover measurements are essential for fit, pricing, and long-term performance. That’s why every custom configuration starts with the Rainstopper Measurement Worksheet. It keeps everyone aligned and prevents surprises later in the process.

A Practical Next Step

Customization doesn’t require having all the answers upfront. It starts with understanding the conditions, the constraints, and the priorities of the project.

If you want to see the available options in one place, or walk through how different configurations work together, visit our customization page. And if questions come up along the way, we’re here to talk them through.

Customization, when done well, isn’t about making things complicated. It’s about making sure the solution fits the system it’s meant to protect.

Questions about custom configurations?

Phone: 318-667-4330
Email: Info@rainstoppercompany.com

At Rainstopper, our manhole inserts have always been made in the United States, not as a marketing slogan, but as a standard. From sourcing materials to fabrication and assembly, every step of our process has remained 100% American-based since day one.

That consistency matters. It means tighter quality control, clearer accountability, and products built to perform in real-world conditions over decades, not just inspection cycles. It also means the people designing, building, and testing our products understand the infrastructure systems our customers work in because they work in them too.

Today, that long-standing approach aligns directly with the Build America, Buy America (BABA) requirements. Rainstopper manhole inserts meet federal standards for domestic sourcing, which makes them a straightforward choice for infrastructure projects requiring compliance. For engineers, contractors, and municipalities, that clarity helps keep projects moving without added uncertainty.

If you’re navigating BABA compliance on an upcoming project, we’re here to make that part simple. Clear documentation, straightforward answers, and products that already meet the requirements.

When you choose Rainstopper, you’re choosing a company that has consistently supported American manufacturing: steel, skilled labor, and local communities included. We’ve been doing this since 1969, long before it became a requirement.

Thank you for the trust you place in us, and for partnering with us to build and maintain infrastructure that communities depend on.

Questions about BABA compliance or product specifications?

Phone: 318-667-4330
Email: Info@rainstoppercompany.com

At Rainstopper, patents are not about protecting ideas for their own sake. They exist to solve problems that show up in the field, day after day, manhole after manhole.

Over the years, we have developed and secured multiple U.S. patents related to manhole inflow protection. Each one came out of a specific challenge that municipalities, engineers, and crews were already dealing with. The goal was never novelty. The goal was reliability, safety, and fewer headaches after installation.

Designed Around Real-World Use

Every patented feature in a Rainstopper insert addresses a practical issue:

Tetherlok System
Prevents theft, loss, and accidental drop-through during inspections or maintenance. Inserts are secured to the manhole frame with a braided stainless steel cable, and the cover cannot be replaced until the insert is properly reattached. This prevents costly retrievals and ensures accountability.

50-Year Gasket
Addresses premature seal failure. Engineered and tested to withstand long-term exposure to water head, pressure, and environmental stress without leaking. Tested at over 16 feet of water head for more than 2,400 hours with zero leakage.

Patented Relief Valve Design
Provides non-mechanical venting of sewer gases. With no moving parts, there is nothing to seize, corrode, or break. The offset placement reduces the risk of damage during routine inspections.

Ribbed Pan Structure
Adds strength where it matters without increasing weight. The design improves load performance while keeping the insert light enough for one-person installation.

None of these features were created in isolation. They were shaped by feedback from the field and refined over time through thousands of real installations.

Patents That Perform Over Time

Innovation only matters if it holds up years after installation. Rainstopper’s patented designs have been used in thousands of manholes across the country, in conditions ranging from flood events and heavy traffic loads to corrosive environments and daily maintenance routines.

That long-term performance is what gives patents their value. Not as documents on paper, but as solutions that continue to work long after the job is done.

Built With Purpose

Rainstopper’s approach to innovation is straightforward: identify a real problem, design a solution that makes work safer or more reliable, test it, refine it, then stand behind it.

Our patents reflect that mindset. They exist to reduce risk, extend service life, and support the people responsible for keeping collection systems running.

Questions about how these patented features apply to your project?

Phone: 318-667-4330
Email: Info@rainstoppercompany.com