Overview 

Large sites cannot manage what they cannot see. A single incoming meter only shows total consumption, not where water is being used, lost or misdirected. This case study brings together several real-world examples to demonstrate how proactive water monitoring, enabled through sub-metering, provides the visibility needed to detect issues early, localise them precisely and act with confidence. 

What Proactive Sub-Metering Enables 

By monitoring both the main revenue meter and multiple sub-meters, sites can: 

• Track usage across different parts of the site 
• Sub-bill tenants or departments accurately 
• Immediately confirm where increases occur 
• Avoid time-consuming surveys 
• Create water balances to expose unaccounted-for use 

Example 1: Weekend Loss Isolated to One Operational Area 

(Blue line = total site | Red line = sub-metered area) 

At a manufacturing site, proactive monitoring detected higher-than-expected weekend flow on the blue line. The red line, representing one sub-metered operational area, also remained active, while earlier weekends showed it dropping to near zero. 

This confirmed the increase was coming from one specific system, not the whole site. 

Value delivered: 
Targeted investigation instead of site-wide disruption. 

Example 2: University Campus – Leak Proven to Be Outside All Buildings 

(Blue = revenue meter | Red & Green = building sub-meters) 

The blue line showed rising water use across the campus, but both the red and green lines remained stable. This proved that none of the sub-metered building areas were responsible. 

The leak was therefore between the revenue meter and the first sub-meter, typically on underground distribution pipework. 

Value delivered: 
No need to inspect or disrupt academic buildings. 

Example 3: Major Burst – Tenants Protected Instantly 

(Blue = revenue meter | Red = combined tenant sub-meters) 

When the blue line surged to nearly 19,000 litres per hour, it indicated a major burst. The red line, showing the total of all tenants sub-meters, stayed close to zero. 

This instantly confirmed the burst was not inside any tenant unit. 

Value delivered: 
Tenants avoided disruption and blame, engineers went straight to external underground infrastructure. 

Example 4: Single Tenant Identified in Minutes 

(Blue = total site | Red = tenant sub-meter) 

During a period of increased use, the blue line rose. Sub-meter data showed only one red line increasing, while all others remained stable. 

This allowed the site to contact the correct tenant directly. 

Value delivered: 
Fast resolution without disturbing other occupiers. 

Example 5: Creating a Full Water Balance 

(Blue = revenue meter | Red = factory sub-meter) 

The blue line shows all incoming water. The red line shows water used inside the main factory. The gap between the two lines represents water used or lost elsewhere. 

This creates a true water balance, revealing exactly how much water is unaccounted for. 

Value delivered: 
Clear separation of production use from losses and inefficiencies. 

Why This Matters 

Proactive monitoring with sub-metering delivers: 
• Faster fault detection 
• Precise localisation 
• Less disruption 
• Fair billing 
• Lower costs 
• Better sustainability reporting 

Conclusion 

These examples show how proactive water monitoring powered by sub-metering gives complex sites the control they need. Instead of guessing where water is going, teams see it clearly, act quickly and protect both operations and budgets.