Thank you very much, Dirprwy Lywydd. We undertook our short, focused inquiry into storm overflows when they were firmly in the public spotlight. There were frequent news headlines about raw sewage being dumped into rivers across England and Wales. There were reports of heated debates in Westminster on tighter laws to tackle sewage spills. Then came Ofwat’s announcement of an investigation into water companies on both sides of the border, which were potentially in breach of storm overflow permits. As a committee, we therefore felt it was important to have a clear picture of storm overflows in Wales and the actions being taken to tackle sewage spills.

So, what do we know about storm overflows? Well, they’re meant to be used infrequently and in exceptional circumstances, when heavy rainfall means that the capacity of the combined sewers is exceeded. They are there as a safety valve so that sewage doesn’t flood back into our homes and onto our streets. However unpleasant, given the damage and distress caused by sewer flooding, they are a necessary feature of the sewer system that we have inherited.  

So, what’s the problem? Well, the figures speak for themselves. Rather than being used in exceptional circumstances only, it appears that storm overflows are the norm. According to NRW, in 2020 there were over 105,000 spills—105,000 spills—from the over 2,000 permitted overflows that are monitored. Is it any wonder, therefore, that the public responded so strongly when these figures were published and that the water companies and NRW were so harshly criticised? And those figures, of course, don't tell the whole story—they don't include spills from permitted overflows without monitors, or from unpermitted overflows. This means that the true number of spills may in fact be much higher.