FAQ: Boil Water Advisories

Below are answers to frequently asked questions about boil water advisories and notices. Click on a question to view the answer.

A boil water advisory is a public statement advising customers to boil tap water before consuming it. An advisory does not mean the water is contaminated but that it could be contaminated. Because the water quality is unknown, customers should assume the water is unsafe to drink and take the appropriate precautions.

A boil water notice is issued when contamination is confirmed in the water system. During the time period of a notice, all affected customers must boil their water before consuming it or use bottled water. Notices will be placed on streets and neighborhoods that are affected.

Boil water advisories are issued when an event has occurred that could allow contaminants to enter the water distribution system. Such events would include a water main break, small or widespread loss of system pressure, or a natural disaster.

In some cases, the town’s field staff can make repairs to a water main while the main is under pressure, which prevents any contamination from the soil and bacteria from entering the distribution system. When this process is used, no boil water advisory is issued.

A boil water advisory also may be issued if a routine water sample tests positive for E. coli. If the routine sample tests positive for total coliform but not E. coli., repeat samples are taken at the same source as well as up and downstream of the source. If the repeat samples are positive for E. coli, a boil water notice must be issued to the affected areas regarding the sample. A boil water advisory may not be issued following the initial sampling result if the cause is known and is being addressed promptly.

The town’s water treatment process removes total coliform bacteria from water, but events such as a water main break or a loss of pressure in the water distribution system may allow these bacteria to enter water lines through cracks in pipes or back-siphoning from a residential plumbing system. Total coliform also can be detected if a dead-end water main has little water turnover. The town can address this by flushing the mains more frequently to ensure the presence of fresh water and appropriate chlorine levels. In any of the above situations, boiling water vigorously for one minute will kill these bacteria and make the water safe to drink.

Total coliform bacteria are a collection of microorganisms that live in large numbers in the intestines of humans and animals, as well as in most soils and surface water. A subgroup of these microorganisms is the fecal coliform bacteria, the most common member being E. coli. These bacteria occur naturally in lakes and streams, but they indicate that the water is contaminated with human or animal waste and may pose a health risk to people who drink it.

The town will notify only the water customers affected or served by the water main being repaired. This notification will be provided by placing door hangers at each customer’s residence. If the advisory is widespread, other appropriate notification measures will be used to assist the town in informing the public.

An advisory or notice will remain in effect until test samples show the water is safe to drink. Notification of the end of the advisory or notice will be issued. Testing for bacteria requires 18 to 24 hours to complete, depending on the type of test used.

The town advises that when water is restored, consumers should boil all water used for human or pet consumption ― including drinking, cooking, brushing teeth, making ice and washing hands ― or use bottled water during the period of the advisory or notice. Vigorous boiling for one minute should kill any disease-causing organisms that may be present in the water.

Infants below the age of 6 months and pregnant women should use an alternate water supply, such as bottled water, whenever possible during an advisory or notice as boiling water concentrates any levels of nitrates that may be present in the water.

The town also encourages water conservation during an advisory or notice.

Yes. Most point-of-use filters are designed to improve the aesthetics of water ― taste and odor ― but not to remove harmful bacteria.

During an advisory or notice, dishes should be washed with hot, soapy water. One tablespoon of bleach per gallon also could be added as a precaution. Dishes then should be rinsed with boiled water. The water will be safe for bathing and washing clothes.

Following an advisory or notice, you may experience discolored water, which can appear to be red, brown or milky and which can be caused by harmless sediment or air bubbles. To clear the discoloration, the town advises you to run cold water through your bathtub or other faucet for 5 to 10 minutes. If discoloration persists, contact the town immediately.