For 150 years an underground reservoir in the heart of Norwich has been supplying water to taps across the city.

The Sultzer Reservoir is one of two underground Victorian treated water reservoirs originally built in January 1871 at Lakenham, which a century and half on are still used by Anglian Water today.

LOOK INSIDE: Norwich's gigantic underground water reservoir

This week marks the 150th anniversary since the little known hidden reservoir was officially opened beginning its hugely important role in day-to-day life in Norwich.

Eastern Daily Press: Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich.Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)

Built in 1871, the Lakenham reservoir is the basin into which all Norwich's water pours after it has come from the River Wensum and been treated at the Heigham Water Treatment Works, and from which it is pumped out to supply the city.

It was built to, and still does, supply Norwich's residents with drinking water.

Eastern Daily Press: Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich.Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)

Paul Naylor, regional supply manager for Anglian Water, said: “The Sultzer Reservoir is one of the oldest and most unique storage facilities we have in our region.

“At 150 years young, it continues to play an important part of the water network in Norwich and ensures the supply of drinking water to our customers in the city and surrounding areas.”

Eastern Daily Press: The outside of Anglian Water's Victorian underground reservoir in Norwich, which has been emptied for inspection. Picture: DENISE BRADLEYThe outside of Anglian Water's Victorian underground reservoir in Norwich, which has been emptied for inspection. Picture: DENISE BRADLEY (Image: Copyright: Archant 2019)

Between them the two underground Lakenham reservoirs store 12 million litres of drinking water before it makes its way to customers’ taps.

Their size means it would take almost three years to fill one of them using a normal kitchen tap.

Eastern Daily Press: Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich.Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)

In 2019, as part of its routine maintenance programme, Anglian Water engineers undertook work to inspect the usually submerged structure of the reservoir to ensure it can continue to supply safe drinking water for decades more to come.

It may be hidden but it's one of the city's architectural marvels.

Eastern Daily Press: The plaque from 1871 when the Victorian underground reservoir in Norwich was built. Picture: DENISE BRADLEYThe plaque from 1871 when the Victorian underground reservoir in Norwich was built. Picture: DENISE BRADLEY (Image: Copyright: Archant 2019)

Nik Shelton, from Anglian Water, labelled it an "absolutely beautiful structure" which was still in great condition despite its ripe age.

"When it was built it was an absolute feat of Victorian engineering," he said.

The Lakenham reservoir is one of more than 500 underground treated water reservoirs Anglian Water uses across the region.

Eastern Daily Press: Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich.Inside Sultzer Reservoir Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)

Unlike the large surface water reservoirs like Alton and Rutland, which store river water before treatment, underground reservoirs hold fully treated, safe, clean drinking water and provide resilient storage at points across the supplier’s 38,000km network of water pipelines.

Eastern Daily Press: Stunning archways and brickwork in Sultzer Reservoir Victorian treated water underground reservoir in Norwich.Stunning archways and brickwork in Sultzer Reservoir Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)

Eastern Daily Press: Inside Anglian Water's Victorian treated water underground reservoir in Norwich.Inside Anglian Water's Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)

Eastern Daily Press: Stunning archways and brickwork in Sultzer Reservoir Victorian treated water underground reservoir in Norwich.Stunning archways and brickwork in Sultzer Reservoir Victorian treated water underground reservoir in Norwich. (Image: Anglian Water)