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Hydrant Flushing Facts & Frequently Asked Questions

Why does the City perform hydrant flushing?

Hydrant flushing is the quick release of water from fire hydrants. It’s a controlled procedure that is vital to the general maintenance of the City’s water distribution system. It ensures adequate water flow is available to fire fighters, residents and businesses. It also helps maintain the City’s water clarity and quality by clearing iron and mineral deposits from the water mains (distribution pipes).

What are the effects of hydrant flushing?

Hydrant flushing helps ensure water quality and helps avoid random bouts of rusty water if there is a high demand for water, such as a major firefighting effort or high usage during a sustained drought.

Sometimes hydrant flushing can make makes the water temporarily appear rust-colored because the iron and mineral deposits in the water get stirred up.

Why is my water rust/tea-colored from the hydrant flushing? Is the water safe?

Sometimes hydrant flushing can make the water temporarily appear rust-colored because the iron and mineral deposits in the water get stirred up. Water is safe to use and consume during hydrant flushing, however it may stain laundry.

The main component of the discoloration of the water during hydrant flushing is caused by iron deposits from inside the water mains. The source of the iron is naturally occurring from ground water wells and deposits in the ductile iron pipe that make up the underground water system. The City has two iron removal systems keeping iron levels in the system’s water around 0.2 part per million (ppm).  Currently, iron is not regulated by the United States Environmental Protection Agency. The Illinois Environmental Protection Agency dictates a current maximum level of 1.0 ppm.  The City’s iron level is historically between 0.0 – 0.265 parts per million. (For reference one part per million is equivalent to looking at 1 inch in 16 miles or 1 minute in 2 years.)

Does the City test the water regularly? Is the testing done at various sites?

The City of St. Charles is required by the U.S. Environmental Protection Agency and the Illinois Environmental Protection Agency to test the water in the system at various times throughout the year according to mandated parameters. The results of these tests are outlined in the annual Water Quality Report available on the City website. (The report is sometimes called the Consumer Confidence Report.) The 2015 report shows the City is in compliance with all the required testing parameters. 

Although the water is discolored during hydrant flushing and may look unclear or tinted, the water is not harmful or contaminated.  To ensure the highest possible quality of water and in accordance with regulations, the City’s Water Division collects samples from 30 separate collection points every month from areas all over of the water system. This sampling takes place even during hydrant flushing operations.  These samples are then analyzed for bacteriological contamination. Historically the City of St. Charles has  compliance with these samples, which means there are no bacteria in the water.

I live on the west side and the City is flushing hydrants on the east side. How come my water is discolored?

Sometimes residents who live beyond the limits of the area where hydrant flushing is being performed will notice rust-colored water. We assure you that the Water Division is making every attempt to keep these impacts to a minimum, while continuing to maintain safe drinking water.

How come my water is discolored, but my neighbor didn’t notice any discoloration?

If you were home when the flushing was going on and you turned on your water, you’re water may be discolored because you are drawing in the water as the city’s system is flushing it and stirring up the minerals and iron.

If your neighbors were not home all day and returned home in the evening and turned on their tap when no flushing was occurring, they most likely will not notice any discoloration.

My water is discolored. What should I do?

Wait until flushing has subsided in your area then run the cold water tap until the water runs clear.
If you have a water softener and are experiencing discolored water, place the unit into regeneration or cleaning mode after hydrant flushing is completed in your area.
Remember rust colored water is safe, but it may stain laundry.  If this happens, keep clothes wet and treat them with stain remover. The City offers free stain remover at:

  • Public Works, 1405 South 7th Avenue
  • City Hall, Reception Desk, 2 East Main Street
  • Police Department, 211 North Riverside Avenue

How often is hydrant flushing done?

Hydrant flushing is performed two times a year—once in the spring and once in the fall.

Tips for Minimizing Water Discoloration during Hydrant Flushing Operations

  • If possible, limit your water use.
  • Wait until flushing has subsided in your area then run the cold water tap until the water runs clear.
  • If have a water softener and are experiencing discolored water, place the unit into regeneration or cleaning mode after hydrant flushing is completed in your area.
  • Remember rust colored water is safe, but it may stain laundry.  If this happens, keep clothes wet and treat them with stain remover.
  • The City offers a stain removal product at no cost and is available for pick up at the following facilities:
    • Public Works, 1405 South 7th Avenue
    • City Hall, Reception Desk, 2 East Main Street
    • Police Department, 211 North Riverside Avenue

For more information, contact the Public Works Department at 630.377.4405 or pw@stcharlesil.gov.

updated Apr 08, 2016