Residents in east Christchurch are being told to boil their water, due to traces of e-coli.

The presence of the bacteria has only been confirmed by a laboratory this morning, after water samples were taken yesterday from the Keyes pump station in Rawhiti Domain.

The pump station provides water to about 2000 homes in the Shirley, Bexley, Wainoni and New Brighton areas.

Christchurch City Council says in those areas, all water used for drinking, food preparation, utensil washing, teeth brushing or for ice, should be boiled until further notice.

The cause of the contamination is not yet known.