CSignum Raises £2.6M to Scale Through-Water IoT Links for Storm Overflow Monitoring

Scottish connectivity company CSignum has closed a £2.6 million funding round to scale manufacturing and commercial deployment of its EM2 wireless communications products. The technology carries sensor data through water, ice, soil, rock and concrete, Ocean News & Technology reports. The Bathgate-based firm also named John Nicholls as CEO.

Existing investors Archangels, PXN Ventures and Scottish Enterprise returned, joined by the British Business Bank and a group of US angel investors.

Electromagnetic Signalling Where Radio Fails

Conventional radio signals attenuate rapidly in water and soil, and acoustic links reflect at the water-air boundary. CSignum’s EM2 system instead uses patented electromagnetic field signalling (EMFS) to pass data from submerged or buried sensors to topside receivers on riverbanks, buoys, piles or structures.

The company says EM2 supports bidirectional links over distances of up to 200 meters. That lets utilities retrofit sensors in storm drains, tunnels and riverbeds without running cables.

Storm Overflow Rules Drive UK Demand

Sales growth has been driven by UK regulation. Section 82 of the Environment Act 2021 requires water companies in England to continuously monitor water quality upstream and downstream of storm overflows and at sewage discharge points.

According to CSignum, utilities must cover 25 percent of England’s more than 14,000 combined sewer overflows during the AMP8 regulatory period to 2030, with the remainder due in AMP9 to 2035. CSignum says it has moved from pilots to volume deployments with several UK water utilities since its £6 million Series A in April 2025.

Pilots in the US, Projects in the Gulf and Asia

Outside the UK, CSignum reports completed pilots with two major US water quality monitoring organizations. It is also supplying communications for a smart buoy project in the Gulf of Mexico and through-ground sensing for a large critical infrastructure project in Asia.

The company’s earlier target markets included offshore wind and oil and gas structural monitoring, aquaculture and under-hull ship monitoring.