Subterra — Rapid Sewer Screening

What We Do

Three answers from
one deployment.

Every time we send a device through your pipe, you get three layers of intelligence back. No shutdowns. No dewatering. We can access pipes that other technologies can not.

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Rapid Condition Assessment

Uncover performance and condition issues in hours, not days or weeks.

Continuous measurement of velocity, depth, and flow behaviour compared to original design specification.

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Red Flags - Focus on Major Issues

360° video captures the pipe wall above and below the waterline. We flag the serious problems; collapsed sections, failed liners, major damage. the things that need action now.

Screening-level visual inspection identifying Grade 4 and Grade 5 equivalent structural defects.
Prioritize MSI and CCTV inspection work.

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Verify — Did the Repair Work?

Had a liner installed? Rehab work completed? Nearby construction impacting your most critical assets?
Hold contractors accountable with real evidence.

Even with the best intentions sometimes material choices or installation methods of the past can cause issues much earlier than expected.

How It Works

Remotely deployed.
Free-floating.
Collected miles downstream.

Video: Deploy

Deploy

Remotely deployed from any accessible manhole

The device fits in a backpack. We open a manhole, place the float on the water surface, and let it go. We regularly get called to pipes that traditional inspection equipment can't access — pipes that are too large, too deep, or too difficult to reach with a tethered robot.

We always send a dummy float first to confirm the pipe is clear and passable. If the dummy doesn't make it through, the instrumented device doesn't go in. Occasionally a dummy will ride all the way to the treatment plant screens — but we've never lost an instrumented device.

Video: Capture

Capture

It rides the flow and records everything

The float travels with the sewage — up to 2 miles in a single run. It continuously measures how fast the water is moving, how deep it is, and records 360° video of the pipe wall above and at the waterline.

Sensors record velocity, depth, and flow behaviour every fraction of a second. The camera captures the full pipe circumference — above and below the water surface.

Video: Retrieve

Retrieve

Collected at an accessible location downstream

We collect the device at the next accessible point downstream — a manhole, a junction structure, or another access point. The whole run typically takes minutes, not hours. In Washington DC, we floated under Nationals Park baseball stadium in a matter of minutes, opening just two manholes.

DC requires a permit for every manhole opened. Fewer manholes means fewer permits, less traffic disruption, and faster mobilisation. This access advantage is why we get called for pipes that traditional equipment can't reach.

Example inspection dashboard showing map, metrics, and recent inspections

Deliverable

Reports

Structured deliverables your team can act on

After each run you receive clear documentation — not raw files to decipher. Performance summaries, flagged locations, and video references are packaged so engineers and asset managers can prioritise follow-up, justify spend, and track conditions over time.

Typical outputs include screening summaries, performance visualisations, red-flag defect listings with supporting clips, and recommendations for targeted CCTV or rehabilitation where it matters most.

Frequently Asked Questions

Can you see under the water?

While we don’t rely on visual imagery, Subterra captures detailed information about its movement and how the water behaves as it travels through the pipe. The real insight comes from our data, and we measure what the water is doing, not just what the pipe looks like. Our flow profiling highlights conditions and anomalies in areas traditional cameras can’t see, giving you visibility where it matters most.

How do you ensure a successful deployment?

Every deployment begins with a decoy float run. If the decoy does not successfully pass through the pipe segment, the instrumented device is not deployed. This step helps confirm clear passage, ensures proper timing for deployment and retrieval, and verifies that no major obstructions exist within the segment being screened.

Can you detect defects?

Yes. subterra identifies and flags serious structural concerns, such as Grade 4 and Grade 5 conditions, in accordance with industry standards. Think of it as a security screening for your wastewater assets; we rapidly assess the entire pipe and flag areas that warrant attention. If something triggers concern, you can then decide whether follow‑up action or a targeted inspection is needed based on the asset’s overall condition.

Proven In The Field

Not a concept.
Deployed at scale, peer-reviewed.

We've screened America's most critical interceptors, and an independent engineering firm published the results in the nation's top civil engineering journal.

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Peer-Reviewed & Published
ASCE Pipelines Conference 2024

Major Sewer Emergency Leads to Validation

When a Los Angeles treatment plant failure sent emergency flows through the city's largest interceptors, subterra screened 51,409 feet in 3 hours 48 minutes. Brown and Caldwell independently authored and published the methodology and results through the American Society of Civil Engineers.

Read the Research

51,409 ft

Screened in a single emergency response

3h 48m

Total deployment time

Brown & Caldwell

Independent third-party author

ASCE

Published in Pipelines 2024

Trusted by leading engineering firms & wastewater utilities

Field Footage

What we actually see
down there.

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Navigating Obstacles

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Regulatory Alignment

This is what EPA's CMOM has been
asking for since 2005.

The EPA's CMOM framework requires predictive, performance-based asset management. For large gravity interceptors, the practical tool to deliver this hasn't existed until now.

CMOM Requires

subterra Delivers

Predictive maintenance with baselines

Detects hydraulic warning signs before visible failure

Capacity evaluation

Measures actual capacity as a % of design on every run

Performance-based rehab decisions

Individual grades from measured data — not age assumptions

Baseline and trend analysis

First run = baseline. Every run after measures change from it

Reactive → Predictive shift

Annual screening converts emergencies into budgeted maintenance

For Engineering Consultants & Operators

Creating A Screening Program?

subterra's screening-first methodology lets you cover more of your collection system within the same budget, and demonstrate CMOM compliance that protects the utility and the communities they serve.

"Condition assessment shall include both structural evaluation and hydraulic performance assessment comparing observed in-pipe flow behaviour to design parameters."

Know which pipes need attention.
And which ones don't.

Three answers from
one deployment.

Rapid Condition Assessment

Red Flags - Focus on Major Issues

Verify — Did the Repair Work?

Remotely deployed.
Free-floating.
Collected miles downstream.

Deploy

Capture

Retrieve

Reports

Frequently Asked Questions

Can you see under the water?

How do you ensure a successful deployment?

Can you detect defects?

Not a concept.
Deployed at scale, peer-reviewed.

Major Sewer Emergency Leads to Validation

Deployed across
North America.

What we actually see
down there.

Navigating Obstacles

This is what EPA's CMOM has been
asking for since 2005.

Creating A Screening Program?

Ready to get started?

Know which pipes need attention.And which ones don't.

Three answers fromone deployment.

Rapid Condition Assessment

Red Flags - Focus on Major Issues

Verify — Did the Repair Work?

Remotely deployed.Free-floating.Collected miles downstream.

Deploy

Capture

Retrieve

Reports

Frequently Asked Questions

Can you see under the water?

How do you ensure a successful deployment?

Can you detect defects?

Not a concept.Deployed at scale, peer-reviewed.

Major Sewer Emergency Leads to Validation

Deployed acrossNorth America.

What we actually seedown there.

Navigating Obstacles

This is what EPA's CMOM has beenasking for since 2005.

Creating A Screening Program?

Ready to get started?

Know which pipes need attention.
And which ones don't.

Three answers from
one deployment.

Remotely deployed.
Free-floating.
Collected miles downstream.

Not a concept.
Deployed at scale, peer-reviewed.

Deployed across
North America.

What we actually see
down there.

This is what EPA's CMOM has been
asking for since 2005.