By CBSBoston.com Staff

NATICK (CBS) – Natick residents are being asked to boil their water after 9 out of 12 water samples tested positive for E. coli.

The samples were collected from 12 sites in the water system Tuesday, and on Wednesday, the town sent out a notice directing all residents to use bottled water or boil tap water for one minute before using it.

According to the notice, the presence of E. coli bacteria indicates water may be contaminated with human or animal waste. Contamination can occur from runoff during heavy rains or a pipe break.

E. coli can cause diarrhea, cramps, nausea, headaches and other symptoms. The bacteria can be especially dangerous for infants, young children, the elderly and people with compromised immune systems.

The notice said the water department hopes to have the issue resolved in a couple of days. In the meantime, water sources that tested positive for E. coli were removed from operation and the town has increased water disinfection treatments.

The town also provide links to the state’s Consumer Information on Boil Orders and Boil Order Frequently Asked Questions.

CBSBoston.com Staff