Fly-tippers have risked contaminating the water supply after dumping 174 metal drums containing paint and solvents.
A member of the public alerted Portsmouth Water to the drums which were ruptured and leaking in three locations in the Lovedean area near Portsmouth on October 25.
A spokesman for the water firm said: “On arrival it was observed that a number of the drums were ruptured and leaking, causing a real risk of contamination to the chalk aquifers below the surface.
“The drums were in a location that was close to Portsmouth Water’s Lovedean borehole and pumping station.
“The potential pollution associated with the paint and solvents posed a real risk to the water supply and so Lovedean Pumping Station was turned off immediately.
“The water supply network was reconfigured to ensure customers’ supplies were unaffected by any potential risk of contamination and any loss of supply.”
The spokesman said it contacted the Environment Agency and took “immediate action” by bringing in specialist contractors Adler and Allan to remove the drums and clean up the contaminated land because heavy rain was forecast.
Bob Taylor, chief executive of Portsmouth Water, said: “I worry about the fact that these incidents are happening and that people don’t seem to understand that illegal dumping of chemicals like these can lead to longer term impacts on the underground aquifers.
“This is the single biggest risk we face as a business.”