Sewage overflow numbers are not quite what you might think - or are being told

This is particularly shocking:

Sewage spills by water firms have risen 29-fold over the past five years, official data reveals.

The number of times raw sewage has been dumped into rivers and lakes across the country has risen from 12,637 in 2016 to 372,533 last year, according to the Environment Agency.

Shocking because, as presented, it’s simply not believable. The water system has become 29 times worse in just the past 5 years? No, really, it hasn’t. That just doesn’t pass the smell test.

A growing population as well as heavier and more frequent storms has led to excessive amounts of sewage getting dumped into other water sources, according to the Department for Food and Rural Affairs (Defra).

Sure, that might have an effect but it would be pretty marginal. Not x29.

….part of the increase shown in the figures is down to better monitoring from water companies over time.

Ah, what part though?

Which brings us to this:

The Environment Agency (EA) and Ofwat have launched a major investigation into sewage treatment works, after new checks led to water companies admitting that they could be releasing unpermitted sewage discharges into rivers and watercourses.

New checks, is it?

In recent years the EA and Ofwat have been pushing water companies to improve their day-to-day performance and meet progressively higher standards to protect the environment.

As part of this, the EA has been checking that water companies comply with requirements and has asked them to fit new monitors at sewage treatment works.

Higher standards and more monitors, is it?

At which point what is really happening becomes clearer. More monitoring of sewage overflows is happening - therefore more sewage overflows are being found.

This all leaves entirely open what is the correct number of such overflows to be having. So too the cost of not having them. Even, is the state owned water system in Scotland doing better or worse by this same measure? Are they, in fact, measuring the same thing in the same way?

But those larger questions can be put aside for a moment or two. The x29 increase in detected sewage overflows is a result of more detectoring of sewage overflows going on - not some catastrophic change in the performance of the sewage system.

Think on it - if the system goes looking for more overflows under tighter standards of what constitutes an overflow then more overflows are going to be found, aren’t they? Which does mean that a claim about an increase in overflows happening, rather than an increase in overflows being detected, is more than a little mendacious.