Five oak-lined wells, one built between 719 and 396 BC, were found on Southern Water's Otterbourne to Southampton pipe route. Updated November 2026.

Five wooden water wells, the oldest built in the Early Iron Age, have been found in Hampshire by archaeologists working ahead of Southern Water’s new pipeline from Otterbourne to Southampton. Radiocarbon dating of one of them puts its construction between 719 and 396 BC, Southern Water said on 6 November.

For readers around Petersfield, who live in the shadow of Butser Hill’s Iron Age earthworks and a few miles from the roundhouses of Butser Ancient Farm, this is a rare look at something those sites cannot show: how people of the same period got their water, built in wood that has survived more than two thousand years.

The dig was carried out by Archaeology South-East (ASE), part of the UCL Institute of Archaeology, north of Southampton. Southern Water paid for the excavation before laying the Southampton Link Main, a 19km pipe between Otterbourne and Southampton.

Hollowed oak trunks sunk into a spring

The wells tapped a spring that people used as a water source through the Iron Age and into the Roman period. Four of them are what archaeologists call “hollow log-lined wells”: oak trunks hollowed out and slotted into pits. The largest is 70 centimetres across.

The details are what make them unusual. One was held in place by a ring of stakes. Another was mended while it was still in use, with a wooden shovel blade pushed in to support a broken section. Pottery in and around the wells shows people were still drawing water here in the later Roman period.

Three archaeologists in hard hats and orange overalls kneeling in a muddy, water-filled trench around a hollowed log wrapped in plastic film
Archaeologists from UCL Archaeology South-East around a hollowed-log well wrapped for lifting. Photo: supplied by Southern Water, credit UCL Archaeology South-East

Rachael Geoghegan of UCL Archaeology South-East, who led the excavation, said the ground itself did the preserving:

“It is rare and exciting to find wooden structures from this time period. The oxygen-starved conditions caused by the wet soil around the spring prevented the wood’s decomposition, preserving the ancient timbers in exquisite detail. We can even see axe marks on some of the timbers.”

A Roman well built a different way

The fifth well is Roman, and its builders did not use a hollow log. They dug a shallow rectangular pit and lined it with timber planks and stakes. Early identification suggests this one was mostly oak too, with large timbers and roundwood stakes showing that wood came from both saplings and older trees.

Hannah Street, a waterlogged wood specialist at UCL Archaeology South-East, described lifting the finds:

“It’s a great opportunity to work on a site with such exceptionally well-preserved wood. Working closely with our conservator we carefully lifted the Iron Age hollowed logs in as complete a condition as possible. The Roman well in particular required meticulous excavation and recording to untangle the different phases of its timber construction. Together these wells provide a fascinating window into how technology developed from the Iron Age through to the Roman period, revealing changing approaches to construction and water management.”

A digital model of a dark brown hollowed oak log, open at the top, shown against a grey background
A digital model of one of the hollowed-log wells. Image: supplied by Southern Water, credit UCL Archaeology South-East

What happens to the wood now

The work is not finished. The archaeologists hope the older trees used in the Roman well will give a precise building date through dendrochronology, which matches the pattern of a tree’s growth rings to show when it was felled. Specialists at Archaeology South-East are also still working through finds and soil samples from the wells. Pollen and plant remains could show what people were doing around the spring, what the landscape looked like and when the wells stopped being used.

The pipeline that found them

Southern Water says it is spending more than £100 million on the Southampton Link Main, and that the scheme will help close a drought-period shortfall of around 200 million litres a day that it says Hampshire faces.

Phil Maunder, the project manager at Southern Water, said:

“This is a terrific find and one that contrasts a two-thousand-year-old water source with a modern water project. There are many exciting aspects to major projects, and this is a great example. We’re investing more than £100million in the Southampton Link Main (SLM) project and once operational, the project will play a vital role in keeping Hampshire’s taps and rivers flowing for future generations.”

What it means for you

  • Nothing to do or avoid locally. The dig and the pipeline are on the Otterbourne to Southampton route, outside East Hampshire, and Southern Water has not given the exact site.
  • More results are coming. A firmer date for the Roman well, and what the pollen and plant remains show, will follow once the specialists finish their analysis.
  • To see Iron Age life up close nearer home, Butser Ancient Farm on Chalton Lane, south of Petersfield, has reconstructed prehistoric, Roman and Saxon buildings and runs Christmas events on dates from 5 to 20 December.