A water main break in Lake Forest that caused low pressure in the water distribution system resulted in the City of Lake Forest activating a boil order Friday afternoon, October 10, 2025 that was extended overnight Saturday and Sunday as a precaution, and lifted at 6:00 a.m. Sunday.
Laboratory test results confirm that the City’s water supply meets all public health standards. Tap water is now safe to drink, cook with, and use for all household activities, according to the City of Lake Forest.
“As an extra precaution, you may choose to run both cold and hot water taps for five minutes each, starting with the lowest faucet in your home (such as a basement or lower-level sink). This helps flush any water that may have remained in your pipes or water heater during the boil order.”
— City of Lake Forest
The boil order was issued on Friday, October 10, following a water main break along Westleigh Road that temporarily affected water pressure in parts of Lake Forest. Crews quickly completed repairs, restored water pressure, and conducted required testing to ensure the water supply remains safe.
“We understand that the boil order created challenges for residents, families, and businesses. Issuing a boil order is not something the City takes lightly. When pressure drops below a certain level, there’s a small risk that contaminants could enter the water system, so the Illinois Environmental Protective Agency requires a boil order until tests confirm the water is safe.
Our top priority is ensuring the safety and reliability of the water supply, and we appreciate your patience as staff worked around the clock to confirm the water was safe to use again.”
— City of Lake Forest
The City of Lake Forest announced the water main break along Westleigh Road in Lake Forest had been repaired, and water pressure had returned to normal throughout the system, as of 9:00 a.m. on Saturday, October 11, 2025. The City of Lake Forest gets its water supply from Lake Michigan, which is drawn through intake pipes and then treated at the Lake Forest Water Plant. The potential water contamination occurred after water was treated and distributed at the Lake Forest Water Plant.
The City of Lake Forest warned that although the return of water pressure is a positive sign, the city cannot confirm the water is safe to drink until the laboratory test results are received. Therefore, out of an abundance of caution, the precautionary boil order remained in place until testing confirms the water meets all public health standards.
The City of Lake Forest expects initial test results by early Sunday morning, October 12, 2025. Based on the test results, the boil order could be lifted or may need to be extended for another 24 hours. Lake Forest promised to provide an update as soon as results are available.
Before 6:00 a.m. Sunday morning, the City of Lake Forest was under a boil order for a third day after a large water main break was discovered Friday afternoon, October 10, 2025.
The city at 4:17 p.m. on Friday, October 10, 2025 issued a citywide boil order due to the water main break that caused a drop in water pressure below Illinois Environmental Protection Agency (IEPA) acceptable levels.
Why Is Low Water Pressure an Issue?
When a water main break occurs, water is usually flowing in the street and buckling pavement, pushing up sod, and throwing silt into the street; the pressure in the underground water main is dropped, and the pressure delivered to residents is lower.
Anytime you see a water main break near your home or your place of employment, you should not drink water from the tap or faucet. You should also stop drinking water from the tap if the water pressure is low coming out of the tap, until you at least find the reason for the low water pressure.
Low water pressure and breaks in the integrity of water pipes can temporarily threaten safe tap water. While a water boil may remedy microbial contamination of drinking water, a water boil treatment does not necessarily rid the water of other contaminants — such as pesticides, petroleum products, fertilizers, etc. that may be in the soil adjacent to a broken water main or other pipe with unknown integrity issues. In other words, we tend to focus on microbes that might make us sick in a few hours or days. But what about contamination by chemicals that might make us sick in years or decades?
Boiling water kills microbes, but remaining water may concentrate chemicals that don’t evaporate with steam rising above the remaining boiling water.
When there are leaks and breaks in the integrity of pipes carrying drinking water that go undetected, the potential for a negative pressure event exists. That means stuff outside the pipes might get inside the broken pipes, and into your drinking water. Normally, high water pressure — above 20 PSI, for example — keeps biological and chemical contaminants outside of the pipes. You don’t want to be drinking water where low pressure inside pipes might be allowing contaminants from nearby sewer lines to be drawn into the pipes used for drinking water. Similarly, you don’t want to be drinking water that might be supplied in pipes that are drawing in soil contaminants where lawn fertilizer, weed killers, or gasoline, etc. are lurking in the soil. What if your neighbor has a leaky septic tank; or think of all the lawn applications of weed chemicals and fertilizers you see in the neighborhood during the summer. You don’t want to be drinking water from low pressure pipes.
Sewer lines carrying feces and human waste are supposed to be a significant distance from drinking water supply pipes, but if a low pressure event is allowing feces and other sewer contaminants to be drawn in to the low pressure drinking water supply pipe from nearby soil contamination that is an issue.
Soil contaminants will flow from a relatively higher pressure to a lower pressure. If contaminants are in the soil — next to a broken water main that no longer has the pressure or integrity to keep chemicals and microbes out — those contaminants can enter the water distribution system. According to the EPA, any contaminant exterior to the distribution system may enter potable water supplies during a negative pressure event. Chemical contaminants could include pesticides, petroleum products, fertilizers, solvents, detergents, pharmaceuticals, and other compounds. Predominant pesticides in urban areas include atrazine, simazine, prometon, and diazinon (Patterson and Focazio 2001). According to the EPA, other studies have detected insect repellants, fire retardants, and other industrial chemicals (Koplin et al. 2002). If chemical compounds intrude in sufficient concentration or volume, they might result in acute toxicity. Microbial contaminants are a concern because even with dilution, some microbes (e.g., viruses) could cause an infection with a single organism, according to the EPA.
The City of Lake Forest advised that the risk of illness is very low, but recommended contacting a healthcare provider for guidance if symptoms such as diarrhea, nausea, vomiting, or stomach cramps occur after drinking the water,.
Helpful Guidance During a Boil Order (from the City of Lake Forest)
Drinking and cooking:
Use bottled water whenever possible. If bottled water is not available, bring affected tap water to a rolling boil for three minutes before use.
Handwashing and oral hygiene:
Use bottled or boiled water for brushing teeth and washing hands.
Bathing and showering:
Affected water is safe to use, according to the City of Lake Forest.
Dishwashing:
Use a dishwasher, if possible. For handwashing dishes, use boiled or bottled water. The affected tap water may be used if the clean dishes are immersed for at least one minute in a sink of water to which one full tablespoon of regular household bleach has been added.
Household cleaning:
Affected water is safe for general cleaning tasks, according to the City of Lake Forest.
Answers to common questions from the City of Lake Forest
How do I know when water is safe to drink?
Once the boil order is lifted, we will share the information across the City’s digital platforms, including social media, email newsletters, website, Lake Forest Now push notifications, and Smart911 text, email, and calls. If you haven’t already, please sign up for Smart911 at www.Smart911.com to receive emergency alerts by text, email, or phone.
How long will the boil order last?
The boil order will remain in effect until laboratory testing confirms the water meets all public health standards. After the water main was repaired, several samples were collected from throughout the system for testing. The City of Lake Forest expects to receive results early Sunday morning, at which point the City can determine whether the boil order can be lifted.
What about risk of illness?
Don’t panic — the risk of illness is very low. During a boil order, if you are in good health, it’s unlikely you’ll get sick from drinking the water. Still, it’s important to be cautious. If you experience symptoms such as diarrhea, nausea, vomiting, or stomach cramps after drinking the water, contact your healthcare provider for guidance.
Can I shower or bathe?
Yes. It’s safe to shower or bathe, as long as you avoid swallowing the water. Remind children not to put water in their mouths. For infants, consider using bottled water or water that has been boiled for 5 minutes and then cooled.
Can my pets drink the water?
Animals generally are not affected in the same way as people by contaminants in the water. If you prefer to be cautious, you can provide your pets bottled water or water that has been boiled for 3 minutes and cooled. Fish tanks are not affected.
When the boil order is lifted, what do we do?
As of Saturday, October 11, the precautionary boil order is still in effect. However, once the boil order is lifted, out of an abundance of caution, you may choose to run both your cold and hot water taps for five minutes each, starting with the lowest faucet in your home (such as in the basement or lower level). This helps flush any potentially contaminated water remaining in the pipes or heater.
What should I do with my ice maker after the boil order, and after the boil order expires?
Discard any ice made during the boil order. Once the boil order is lifted, allow the ice maker to make a fresh batch of ice and discard that first batch. After that, you can resume normal use.
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