'People yearn for stability'

Ageing sewage plant on the frontline of Thames crisis

- Nils Pratley

It is a grey day in a wet week but one of Thames Water's neglected plants is still coping. Wastewater is being pumped into the vast Maple Lodge sewage treatment centre in Rickmansworth, just off the M25, at a rate of about 3,000 litres a second, within capacity.

The site manager points out the first-line screens that catch everything that will not pass through a 5mm filter. A "sheep" - a bundle of wet wipes, sanitary pads, cotton buds, condoms and indigestible bits of sweetcorn - is rotating at one edge. Credit cards and false teeth have been known to end up here.

Maple Lodge is on the frontline of the national sewage scandal and the crisis over Thames Water's future, amid protracted financing talks and the threat of a temporary nationalisation.

The site does not always cope.

Maple Lodge, Thames's fifthlargest sewage treatment centre, discharged 124 times for a total of 1,916 hours into the River Colne during the heavy rainfall year of 2024. In the wet start to January, Thames's real-time portal was showing multiple storm overflow discharges at Maple Lodge, one lasting 66 hours and accompanied by the dreaded words, "this means there could be sewage in this section of the watercourse".

This is one of the facilities that the regulator, Ofwat, was referencing when it fined Thames £104m last year for failures "to build, maintain and operate adequate infrastructure to meet its obligations". About 157 wastewater works were labelled "sites of concern".

To see why Maple Lodge fits the description, gaze across its 10 hectares (24 acres). The place is tidy but unmistakably old, cramped, underinvested and designed to older standards. It is struggling with a growing local population and the sponge-like effects of the chalky landscape.