Across the country, water utilities are modernizing their SCADA systems. One of the most significant trends is the migration away from traditional licensed UHF and VHF telemetry networks over to cellular-based solutions.
On paper, the appeal is obvious: lower upfront infrastructure costs, reduced maintenance, and the convenience of leveraging existing commercial networks. But beneath that convenience lies a growing set of risks that deserve closer scrutiny.
Water SCADA systems are not just another IT application, they are the operational backbone of critical infrastructure. They control pumps, monitor tank levels, manage pressure zones, and ensure safe, continuous delivery of drinking water. When these systems fail, the consequences are immediate and public.
Historically, licensed two-way radio systems operating under Part 90 have provided utilities with something cellular networks cannot: control.
With a private UHF or VHF telemetry system, the licensee controls the network architecture, the coverage footprint, and the access points. These systems are isolated, mission-built, and not shared with millions of consumer devices. They are not dependent on a third-party carrier’s priorities, nor are they exposed to the same broad attack surface as commercial networks.
By contrast, cellular-based SCADA introduces dependencies that utilities do not control. Network congestion, service outages, and carrier-level vulnerabilities all become part of the operational equation.
Recent reporting has highlighted growing concerns about the security of cellular infrastructure and supply chains. An April 15 article from The Hill discussed the proliferation of foreign-manufactured cellular modules in critical systems. Earlier this year, Federal News Network reported on ongoing efforts by foreign adversaries, including China, to exploit weaknesses in telecommunications networks.
Whether these threats are theoretical or active, they underscore a simple reality: the more interconnected and externally dependent a system becomes, the more avenues exist for disruption.
This is not to suggest that cellular technology has no place in utility operations. It can be an effective tool for non-critical monitoring, backup communications, or temporary deployments. But using it as the primary transport layer for mission-critical SCADA functions introduces a level of risk that many utilities may be underestimating.
Licensed telemetry systems, while sometimes viewed as legacy infrastructure, continue to offer unmatched reliability, determinism, and security through isolation. They are engineered for exactly the kind of high-availability, low-latency control that water systems require.
In an era where infrastructure resilience is under increasing scrutiny, the question utilities should be asking is not “What is easiest?” but rather:
“What do we trust to run our system when everything else is under stress?”
For many, the answer still points to licensed, private communications networks.