Hundreds of households are without water or have low pressure, and a local primary and pre-school have closed after a water main burst.
Modbury Primary and Pre-school, which have about 200 pupils, closed after the burst was reported at about 11:00 BST.
South West Water said, external some customers in the south Devon town, which has about 1,500 inhabitants, "may experience lower water pressure than usual or a loss of supply while we undertake emergency repairs".
Repairs would take four to five hours, it added.
More news stories for Devon
Listen to the latest news for Devon
Follow BBC Devon on X, external, Facebook, external and Instagram, external. Send your story ideas to [email protected], external.
Burst Water Main Cuts Supply for Hundreds in Modbury