What is sewer flow monitoring?

Sewer flow monitoring is the continuous measurement of wastewater velocity, depth, and flow rate inside active sewer manholes using area-velocity sensors and cellular telemetry.

What is a sewer capacity study?

A sewer capacity study measures existing flow conditions in a downstream sewer to confirm adequate hydraulic capacity for proposed development. Municipalities require a PE-stamped certification and LVL I & II inspection support letter before issuing building permits.

How long does sewer flow monitoring take?

Capacity studies: 7-14 days. I/I and RDII studies: 30-56 days. Model calibration: 3-6 months. US3 delivers proposals within approximately 24 hours.

Rainfall Dependent Infiltration and Inflow is stormwater entering the sanitary sewer during rain events. It is the primary cause of wet weather sanitary sewer overflows. US3 quantifies RDII using the EPA RTK unit hydrograph method.

Capacity Management Operations and Maintenance is EPA's framework for managing sanitary sewer collection systems. US3 provides the flow monitoring data that forms the evidentiary foundation of CMOM programs.

What states does US3 operate in?

US3 operates in all 50 states with additional coverage in Canada, Mexico, and Puerto Rico. Call (855) 872-8233.

FlexFlow IQ Non-Contact Radar Flow Sensor

How the FlexFlow IQ Works

Many sewer flow meters sit in the flow, where grease, rags, sediment, and debris can interfere with the sensor. The FlexFlow IQ takes a different approach: it mounts on a bracket above the channel and uses two radar beams—one measuring surface velocity and one measuring water depth—to compute continuous flow using area × velocity. Keeping the sensor out of the wastewater reduces fouling and can simplify inspection and maintenance.

Key Specifications

Parameter	Specification
Measurement	Non-contact radar velocity + radar depth; flow, level, and velocity outputs
Velocity range	0.098–65 ft/s (0.03–20 m/s)
Velocity accuracy	±0.1 ft/s (±0.03 m/s)
Level measurement	Up to 131 ft (40 m)
Level accuracy	±0.4 in (±10 mm)
Network interfaces	GSM, Modbus RTU, Sensus FlexNet, LoRaWAN
Power	13.0 Ah lithium-thionyl battery or external 12–30 V; 40 µA normal / 200 mA alarm draw
Enclosure / rating	IP68; depth rating 0–20 m
Operating temperature	−20 °C to 65 °C
Dimensions	130 × 130 × 75 mm
Housing	PPA high-performance polyamide
Cabling	RS-485; extendable up to 1,000 m
Calibration interval	Up to 3 years without site calibration
Approvals	PTCRB, GCF, FCC, CE, RoHS

Why Utilities Choose the FlexFlow IQ

Non-contact measurementThe sensor mounts above the flow, limiting exposure to grease, rags, and debris.
Broad hydraulic rangeDesigned for low-flow depths, high velocities, and surcharge conditions.
Long calibration intervalUp to three years without site calibration can reduce field visits and confined-space entries.
Flexible installationWorks in portable or permanent configurations with mounting-bracket options.
Multiple connectivity choicesWireless GSM, LoRaWAN, and Sensus FlexNet options, plus Modbus RTU and RS-485 integration.
Field-ready enclosureIP68 housing and low-power operation support demanding installations.

Versions & Ordering

Code	Description
FFIQ-FN-Kit	FlexFlow IQ for Sensus FlexNet — wireless flow end-node
FFIQ-GSM-Kit	FlexFlow IQ for GSM networks — wireless flow end-node
FFIQ-LW-Kit	FlexFlow IQ for LoRaWAN networks — wireless flow end-node
FLINT	Installation kit for FlexFlow IQ
US3-DH	Data hosting and monitoring services

Applications

Sewer systemsRivers and streamsCanalsIrrigation channelsProcess-water channelsChannel outlets and inlets

How to Get the FlexFlow IQ

US3 supplies the FlexFlow IQ directly. Contact the US3 team for pricing, configuration, installation, and data-hosting options at 855-USCUBED (855-872-8233) or [email protected].

Frequently Asked Questions

FlexFlow IQ FAQ

Is the FlexFlow IQ a contact or non-contact flow meter?

Non-contact. It mounts above the flow and uses radar to measure both velocity and depth, so it never touches the wastewater and cannot be fouled by grease or debris.

What velocity and depth can the FlexFlow IQ measure?

Velocity from 0.098 to 65 ft/s with ±0.1 ft/s accuracy, and level up to 131 ft with ±0.4 in accuracy, from low flow depths through surcharge conditions.

How often does the FlexFlow IQ need calibration?

It typically runs up to three years without site calibration, reducing confined-space entries and maintenance cost.

How does the FlexFlow IQ transmit data?

Through GSM, LoRaWAN, or Sensus FlexNet wireless networks, or wired through Modbus RTU and RS-485 for direct PLC integration.

Who sells the FlexFlow IQ?

Utility Systems Science & Software (US3) manufactures and supplies the FlexFlow IQ directly; there are currently no third-party distributors.

FlexFlow IQ — Non-Contact Radar Flow Sensor for Open Channel & Sewer Monitoring

Flow measurement without an in-water sensor