The square after Coventry Street on the Monopoly board is theWater Works. London has all kinds of water infrastructure, from sewage treatment works to reservoirs and ring mains, not to mention sewers, pumping stations and the Tideway Tunnel. But I thought I'd visit the largest water treatment works in the capital, measured by capacity in megalitres, which it turns out is beside the Thames and very nearly in Surrey.
Hampton Water Treatment Works
If you intend to draw drinking water from the Thames, best do that upstream of the tidal limit. This was the rationale behind the Metropolis Water Act of 1852 which required that intakes for drinking water could no longer be located along the sewage-infested river below Teddington Lock. The Grand Junction Waterworks Company, the Southwark and Vauxhall Waterworks Company and the West Middlesex Waterworks Company thus joined together to build a water treatment works on the north bank of the Thames between Hampton and Sunbury. A mile upstream from Hampton Court Palace, not far from Kempton Park racecourse, if you're trying to get your bearings.
Initially the works comprised of sand filter beds, a reservoir and three steam-driven pump houses, built in brick in institutionally grand Italianate style. The site was soon expanded and by 1900 there were four reservoirs and 40 filter beds, making Hampton one of the largest waterworks anywhere in the world. At one point the engine houses required over 100 tons of coal a day, supplied by barge and delivered to the site via a small industrial railway. Today Hampton Water Treatment Works covers 160 acres, can pump out 700 megalitres a day and supplies about a third of London's fresh water. And I've been for a walk around it.
Hampton's a charming and historic village, once home to celebrated actor David Garrick, with a heritage core around St Mary's church. Stay downstream of the old Post Office boatyard and you can continue to believe this version, with lengthy riverside gardens and a medieval ferry to whisk you over to Molesey. But upstream all this is abruptly whisked away, indeed the citizens of Hampton sacrificed access to the edge of the Thames over 150 years ago and may never get it back. The first obstructions are the Riverdale and Morelands engine houses, two long brick buildings completed in 1870 and distinguished enough that even the cast iron railings out front are Grade II listed. Neither looks to be part of current operations so my first assumption was 'must be flats' but in fact they were sold off in 2012 to create laboratories to support biotechnological start-ups.
Beyond the traffic lights the heritage buildings continue, as yet unoccupied. The first, with its startlingly rectangular chimney, is the RustonBuilding and is one of the original engine houses on site. A plan to turn it and its neighbours into homes and offices is currently battling through the planning process, the outcome pivoting on the fine balance between the proportion of social housing and the ongoing risk of the interior deteriorating further. It feels wrong that all of this is just round the back of the local library. But eventually the view opens out, past old buildings that look like they still perform some infrastructural function, to reveal a massive open space with watery indentations.
The largest is the Grand Junction Reservoir, which I was surprised to see wasn't full given the amount of rain we've had recently but apparently it's used to balance the flow into the works. It exists to feed water into the ozone plant (or as it says on the sign 'Hampton Ozonation') and looked to be a favourite spot for passing waterfowl. The next two pools were dry, one with JCBs carefully spreading layers of sand or gravel in some kind of sanitation ballet. Hampton has to re-layer its slow sand filters every three years, and I'm pretty sure the diggers were busy building up a special biological filtration matrix which, delightfully, is called a Schmutzdecke.
If you're thinking of visiting Hampton this is by far the best place to get a view across the treatment works, the barbed wire effectively beneath you, so you could stop here and catch the 216 back to Kingston. But I wanted to circumnavigate the site which meant taking a strange hemmed-in footpath between sturdy fences, with the gloopier end of the waterworks to one side and the Stain Hill Reservoirs on the other. It could have been quite oppressive but this green stripe in fact supported a variety of wildlife including butterflies, robins, probably foxes if you come at the right time, and squirrels collecting the bountiful harvest of gale-blown horse chestnuts.
Lower Sunbury Road, where I emerged, is wholly different to Upper Sunbury Road up top. For a start it's much quieter, which was good because only occasional vehicles were splashing up mucky puddlefuls following a recent cloudburst. The waterworks was also much better hidden from view thanks to a strategically planted hedge, hence numerous signs saying 'Warning Sharp Thorns'. Other warning notices here include 'Deep Cold Water', 'Danger Deep Water', 'Keep Out', 'Keep Away' and a more verbose poster so old it features an 071 phone number. Through the branches I just about saw the thirteen parallel filter beds, each long and thin and railing-edged, through which the water for my morning cuppa might have passed.
The Thames isn't far away on the other side of the road but the waterworks hogs that too, every acre hereabouts being valuable. The only gap is for a private sailing club and then, unexpectedly, a grubby carpark filled with motley vehicles and evidence of manual labour. This is the access point for PlattsEyot, one of the larger islandson the Thames and still a working landscape because its boatyards have never been replaced by residential hideaways. It was first used for boatbuilding in 1868, then during WW1 as a secret construction site for torpedo-skimming motor launches, and was connected to the Middlesex bank during WW2 by the Royal Engineers. Their bridgestill stands and can only be driven across in something small, hence the makeshift Thames-side car park.
A fire three years ago caused nasty damage to some of Platts Eyot's remaining boatyards and destroyed a Dunkirk Little Ship which was being repaired at the time. Just don't expect to head across the bridge to take a look because the island's private, and is actually bestseen from the Surrey bank so best move on. All that follows is yet more well-screened waterworks perimeter plus the fortified main entrance and a scattering of functional definitely-not-listed buildings. Ahead are the traffic lights I mentioned five paragraphs ago where I took a last glimpse at the multiplicity of filter beds, their output ultimately linked across London via the Thames Water Ring Main. Hampton Water Works may go generally unseen but give thanks it's been doing its intended job for over a century and a half.
