Rethinking hot water safety in a net-zero context

In many organisations, compliance with Legionella regulations is a well-established routine: maintaining elevated water temperatures, flushing outlets regularly, and logging the activity. These measures are vital for safety, but they weren’t designed with energy or carbon efficiency in mind.

Domestic hot water systems are often significant energy users, yet their impact is frequently overlooked in broader sustainability strategies. Especially in large or complex buildings, maintaining consistently high temperatures across an entire network can come at a notable carbon cost.

A balance between risk and efficiency

Much of the current approach stems from a desire to avoid risk. Heating water above 60 °C offers reassurance that bacterial growth is being controlled. But this often results in systems running constantly, regardless of actual usage or need. In practice, that could mean heating and reheating water that’s never used, or flushing litres down the drain as part of routine checks.

It raises a question worth exploring: are all the measures in place today still necessary in every context, or are some driven more by precedent than performance?

Understanding actual demand, outlet use, and temperature trends may help reveal where adjustments are possible – without compromising safety. But doing so requires the right data and a willingness to reassess long-held assumptions.

A more integrated view

Rather than viewing compliance and carbon as competing priorities, there may be scope to align them. Tools now exist to monitor temperature patterns more closely, control systems more precisely, and target interventions where they’re most needed.

Some organisations are already starting to explore this intersection – using insight to reduce energy use while continuing to meet safety requirements. It’s not about lowering standards, but about working smarter within them.

For organisations aiming to reduce operational emissions, domestic hot water systems may offer more opportunities than previously thought. The question is no longer just how to stay compliant, but how to do so in a way that also supports broader sustainability goals.