A central source for insights, tools, and updates on acoustic sewer inspection technology, wastewater infrastructure assessment, and cost-effective solutions for municipal inspection services and collection system optimization.
The SL-RAT is a portable acoustic device engineered to assess blockage conditions in small-diameter gravity sewer lines. In just a few minutes, it provides a score indicating the flow capacity of the pipe.
With the ability to screen thousands of feet per day, the “RAT” helps public works departments quickly identify problem areas and reduce unnecessary cleaning. It supports a shift to condition-based maintenance, where cleaning decisions are based on actual system conditions—not historical schedules—so crews can focus time and budget where it’s truly needed.
SL-DOG is the digital platform that captures, organizes, and visualizes SL-RAT inspection data, helping utilities turn acoustic results into long-term operational insights.
Designed for utility workflows, SL-DOG makes it easy to document inspections, track trends, and integrate with existing systems for better planning and reporting.
Log in from anywhere to review, manage, and share inspection results securely.
Export data to ArcGIS, Google Earth, or Excel to work in existing systems.
Visualize sewer lines, scores, and inspection status in an intuitive map interface.
Monitor trends over time to identify recurring issues and system changes.
Add notes, IDs, and attributes to each inspection for better context and reporting.
Every SL-RAT purchase includes one year of SL-DOG access followed by annual renewal.
Learn how a 54-mile sewer line inspection pinpointed just one mile needing cleaning, leading to thousands of dollars in savings.
Explore how acoustic inspection confirmed a system was 86% clear, enabling rapid, targeted follow-up.
Read how crews prioritized cleaning and CCTV inspections across 11.6 miles of gravity sewer using acoustic data.
Discover how a 1,100-mile collection system has been supported by scalable SL-RAT inspections since 2015.
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Our technology relies on the fact that sound traveling through air mimics the flow of water through a pipe. We use an active transmitter – think of it as the part “yelling” down the pipe, coupled with a receiver – the “brain” that uses sophisticated algorithms and a patented process to interpret blockages based on what it “hears” coming through the pipe.
Acoustic inspection technology uses sound waves to detect blockages in sewer systems. It starts with a stress or sound emission which is then used to generate and transmit wave propagation which travels through the pipe and it’s material. Sensors on the other end convert this to voltage, which is then read and analyzed with an AE instrument for evaluation.
First, set the SL-RAT transmitter device on the open manhole lid. Place the receiver on the other manhole. Then push the start button on the transmitter device. You may want to be ready to adjust the volume. After two minutes, the reading is ready (the SL-RAT stops automatically when the assessment is complete). The display shows whether the sewer pipes are good or blocked, with a score ranging from 0 to 10.
A pipe in a sewer line segment can detect a blockage in less than five minutes once the manhole covers are open. The SL-RAT typically takes 1.5 to 3 minutes to assess automatically. The time depends on the number of test cycles the device performs. A two-person team on average can inspect 50-60 segments covering 8,000 – 10,000 feet (2,500 – 3,000 meters) of pipe per day independently, and without the need of a cleaning crew for support. Our customers have found it possible to inspect up to 6 miles (9,000 meters) per day. Factors impacting time include topography, traffic control needs, and the ease of finding manhole lids.
Compared to CCTV, the SL-RAT can provide a blockage assessment 10-20x faster and for less than 1/10th to 1/20th the cost per foot. Additionally, with SL-RAT there is no pre-cleaning or contact with the waste flow. Our technology is best for quick and low-cost screening of small diameter pipes, although it is limited to pipes under 18 inches in diameter. On the other hand, a zoom camera’s sight distance is greatly limited by small-diameter pipes.
SL-DOG provides a convenient method for archiving, validating, visualizing and analyzing the SL-RAT measurement data. The secure cloud-based web portal compliments your acoustic inspections, facilitating collection system maintenance management.
