A road will close tonight after private contractors blocked a sewage pipe with concrete.
Thames Water has been dealing with a blocked sewer in Watling Street near Radlett Station since February 19.
It has now emerged the sewer had been completely blocked with concrete, causing waste to back up.
The road will be closed from 8pm tonight until 8pm on Saturday while the water company removes the pipe, which is deep under the centre of the road, and replaces it.
Hertfordshire County Councillor Terry Douris, who is responsible for highways said: “We are doing everything in our powers to limit the disruption caused during this time. We are insisting that works be carried out 24/7 to minimise the duration of the closure with noisy works kept to a minimum during the night time periods.
“We are extremely frustrated this situation has arisen due to what appears to be someone’s irresponsible actions and residents affected by this disruption have our sympathy. Due to the nature of these works council taxpayers will not be footing the bill.”
Thames Water operations manager Mark Grimshaw said: “Normally blockages are caused by fat, oil and grease building up in the sewer but unfortunately in this case it’s concrete, so we can’t just jet it through.
“It’s in there and it’s set to the pipe, so we need to remove the pipe and replace it with a new one. This is very frustrating and not the first time damage has been caused by private contractors pouring concrete into our sewers.
“Our main priority is to fix the problem and restore normal service as soon as possible, and then reclaim the costs from whoever is responsible.”
The road is likely to be closed from A411 Elstree Crossroads North to the A414 North Orbital Road.
However the excavation will only fall within a small section of the road, meaning residents will be able to get through.
A fully signed diversion will be in place via the A414 North Orbital Road roundabout, A405 North Orbital Road, A405 Kingsway, A41 North Western Avenue and A41 Colney Way.