A boil water advisory was issued Wednesday night for the entire District of Columbia and Arlington County. The Pentagon, Arlington National Cemetery and Reagan National Airport are also affected.

The Army Corps. of Engineers saw increased cloudiness — called turbidity in technical terms — in water taken from the Washington aqueduct, which services the District and Arlington County. Turbidity could provide a medium for microbes to grow and could indicate the presence of disease-causing organisms, the water authority says.

The advisory is precautionary, and affected residents should boil any water that will be drunk or ingested. DC Water said that cold water should be run for two minutes prior to boiling. Water should be brought to a rolling boil for one minute before cooling and storing in a clean, covered container.

DC Water has also advised residents to discard any beverages and ice made after 9 p.m. on Wednesday.

Bottled water can be used for drinking, brushing teeth, preparing and cooking food, washing fruits and vegetables, preparing infant formula, making ice, washing dishes by hand and giving water to pets.

DC Water says the increased cloudiness means water treatment must be adjusted to account for any potential contamination.

The advisory will be in place until testing confirms the water is safe to drink.

This article was originally published on NBCNews.com