To leak or not to leak, that is the question?

To leak or not to leak?


Well not all high water bills are caused by water leaks underground, if the water consumption is considered high on your water bills it should be classed as an “unaccounted water loss” which means that a detailed site survey is needed to accurately quantify the reason(s) for the high water consumption.


Here at H²O Building Services more and more site water audits are reporting quite significant water losses through either old or poor quality water fittings, in particular the old and trusted w.c cistern! Generally the last place to check for water losses but certainly in offices or accommodation blocks the w.c cistern is on the list and indeed does get dismissed by a great many water audit surveys. Just imagine of there are 150 w.c cisterns and each one needs checking!

Like it or not it comes with the territory, though detailed investigations will always pay dividends and here is a startling example of a lack of attention to detail.


Site: Large student accommodation block with 180 beds compromising showers, wash hand basins, w.c cisterns with an annual water bill of £62,000.

Desktop water audit indicates a £30,000 per year overspend.


On inspecting the water meter there was a water flow data logger installed, we were able to access the water flow data via the internet and download the usual flow profile. This indicated a night time and continual base load of 1.36m3 per hour, over a year 11,900m3 of water at a cost of £31,000. This concurred with the initial desktop water audit findings.


Below is a copy of the water flow data logger visual flow profile, you may note the graph never goes below 1.36m3 continual flow, now we have conclusive proof of the water loss.

Visual flow profile - Leak or not to Leak


The site had 5 floors with a controlling isolation valve on each floor located in the services duct. Each isolation valve was shut then starting at the top floor the valve was opened and the flow rate was recorded by an engineer viewing the water meter. 3 floors indicated high demand when the valves were opened demonstrating an internal problem. Upon inspection the w.c cisterns on each of the 3 floors 21 were found to be leaking. On an individual basis the water loss does not seem very significant, below is just one example.


The recommendation is that all fittings are replaced to a more simplified design saving £31,000 per year on water costs and 2.1 million gallons of water!

When the fittings have been replaced the visual flow profiles will be downloaded to ensure target water savings have been achieved and the water flow will continue to be remotely monitored to ensure water savings are  maintained.


High water bills?

You will find us on the internet type – Water Audit Experts into your search bar.

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H20 Building Services - leak or not to leak