A boil water advisory is a notice from your water provider that tap water may not be safe to drink without boiling first. In St. Louis, these notices can cover a single block, a neighborhood, or a larger service area, and they often arrive on short notice. This guide explains what the notice means and what most homeowners in the St. Louis area can do once it has ended. It is a general reader resource, not a substitute for the notice itself, which always controls.

What the advisory means

Water providers issue boil water advisories when they cannot confirm that water in part of the system is safe from microbes. Common triggers include a pressure drop, a main break, repair work, or a problem found during routine sampling. The advisory tells you what to do while it is in effect, usually including boiling water used for drinking, cooking, brushing teeth, and preparing infant formula. Read the notice closely, since the instructions and the affected area can change from one event to the next.

Your address matters. Homes in the City of St. Louis and in the surrounding county may be served by different providers, and a notice may cover only part of a service area. If you are unsure whether your home is included, check the notice itself or the provider's official channels rather than relying on a neighbor's account.

While the advisory is in effect

  • Use bottled water or water you have boiled, following the notice's guidance on how to boil.
  • Let boiled water cool in a clean, covered container, and store it away from dust.
  • Avoid using ice from your freezer or ice maker unless the notice says it is safe.
  • Keep the notice where everyone in the home can see it.

Confirm the advisory has actually ended

Do not rely on a timeline you assumed. Wait for an official lift notice from the provider. Some advisories end for part of an area first, and some are lifted only after sampling results come back. Once you have the lift notice, check whether it includes special steps, such as flushing lines or running taps before use.

Steps after the all-clear

  1. Read the lift notice in full and note any flushing instructions.
  2. Run cold taps in each area of the home, starting with the one farthest from where water enters the house, until the water runs clear and steady.
  3. Clean faucet aerators, which can trap debris that loosened during the event.
  4. Discard ice made or stored during the advisory, then wash the ice bin and run the maker through a fresh cycle before using it.
  5. Replace any filter cartridges that the manufacturer's label or your household routine calls for after a disruption, and follow the cartridge's own flushing instructions.
  6. Run the dishwasher and washing machine on normal cycles, then check the water for odor or color before relying on it.

Water heater and hot taps

Run hot taps after cold taps, since the water heater may hold water that entered during the event. If the lift notice mentions the heater, follow its directions. Do not drain a water heater for flushing unless the notice or the appliance manual calls for it, and take care with hot water when you do.

Ice makers and dispensers

Ice trays, bins, and refrigerator water dispensers can hold water that was not safe during the advisory. Empty and wash them, then discard the first batches of ice and water after the all-clear.

Home testing and what it can and cannot tell you

Home test strips and kits are useful for hardness, chlorine, and some other everyday measures, but most do not check for the microbes a boil advisory is meant to address. Treat the provider's lift notice as the authority on safety. If your home uses a private well rather than city or county service, the situation is different, and the lab you use for sampling is the place to ask which tests apply.

When to get outside help

Contact your water provider if the water stays discolored, smells unusual, or does not match what the lift notice describes. If anyone in the home has concerns about their health after using tap water during an advisory, speak with a health care professional, who can advise on your specific situation.