IL / Northbrook
IL · Tap water records
Northbrook tap water, in plain English
Here is what the EPA's own data shows about tap water in Northbrook. According to EPA SDWIS data retrieved June 2026, Northbrook is served by 12 active community water systems, together reported to serve about 45,899 people.
As of June 2026, EPA records show 135 violations across the community water system(s) serving Northbrook, going back to the earliest EPA record. 1 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
What the EPA has on record, by system
Northbrook
34,407 served · surface water · PWSID IL0312070 - Health-based Lead and Copper Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in January 1993. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Orthophosphate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
- Monitoring pH: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Alkalinity, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in July 2023. EPA records do not show all of these as returned to compliance.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in December 2020. All have since returned to compliance, per EPA records.
Oasis Mhp
3,000 served · groundwater · PWSID IL0315185 - Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in September 2021. EPA records do not show all of these as returned to compliance.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in September 2021. EPA records do not show all of these as returned to compliance.
- Monitoring Antimony, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Sodium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Iron: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Cadmium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Zinc: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Thallium, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Beryllium, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Nickel: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Selenium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Barium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Mercury: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Total Polychlorinated Biphenyls (PCB): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
- Monitoring Gross Alpha Particle Activity: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2017. EPA records do not show all of these as returned to compliance.
- Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2017. EPA records do not show all of these as returned to compliance.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2012. All have since returned to compliance, per EPA records.
Mission Brook Sd
2,852 served · surface water · PWSID IL0315920 - Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between October 2024 and July 2025. EPA records do not show all of these as returned to compliance.
Sunset Mhp
1,400 served · surface water · PWSID IL0310080 - Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between April 2018 and December 2020. All have since returned to compliance, per EPA records.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2011 and July 2016. All have since returned to compliance, per EPA records.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in May 2008. All have since returned to compliance, per EPA records.
Oakbrook Estates Mhp
1,012 served · groundwater · PWSID IL1115125 - Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between October 2024 and July 2025. EPA records do not show all of these as returned to compliance.
Harbor Point Estates Mhp
950 served · surface water · PWSID IL0317010 - Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2025. All have since returned to compliance, per EPA records.
- Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between January 2024 and January 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between January 2024 and January 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between January 2024 and July 2024. All have since returned to compliance, per EPA records.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2024. All have since returned to compliance, per EPA records.
Cambridge Courts Mhp
658 served · surface water · PWSID IL0971540 - Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between April 2023 and July 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between April 2023 and July 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2024. All have since returned to compliance, per EPA records.
Harvest View Mhc
400 served · groundwater · PWSID WI2520201 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cedar Haven Mhc
395 served · groundwater · PWSID ME0007363 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Whispering Lakes Water System, Inc.
375 served · groundwater · PWSID IL0970220 - Monitoring Gross Alpha Particle Activity: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times in January 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times in January 2024. EPA records do not show all of these as returned to compliance.
Brookside Meadows Mhp
250 served · groundwater · PWSID WI2671738 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Roaring Fork Mhp
200 served · groundwater · PWSID CO0149685 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.