More than 60 households have been left without drinking water after heavy rains resulted in supplies being contaminated with slurry.
The problem was first identified after one person in the picturesque village of Firle, near Lewes, complained of a stomach bug.
Water for the homes in the village comes from a private supply on the Firle Estate, where most of the residents are estate workers.
Managers of the estate, which is owned by Viscount Gage, called in public health officers from Lewes District Council a week ago.
They have tested the supply and offered residents bottled water and advised them to boil tap water before use.
A spokesman for the council said: "When the council tested the water, they found it to be contaminated and we asked the Firle Estate to close down the supply while tests were carried out into what was the cause.
"It is believed the water was contaminated by slurry washed from the fields by heavy rain, but the tests have not come back yet."
It is not thought the stomach upset was caused by the water as it has remained an isolated incident.
It is hoped water supplies will be restored in the next couple of days.
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