PA / Twin Rocks
PA · Tap water records
Twin Rocks tap water, in plain English
Here is what the EPA's own data shows about tap water in Twin Rocks. According to EPA SDWIS data retrieved June 2026, Twin Rocks is served by 1 active community water system, together reported to serve about 1,650 people.
As of June 2026, EPA records show 70 violations across the community water system(s) serving Twin Rocks, going back to the earliest EPA record. 36 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
Blacklick Valley Muni Auth
1,650 served · surface water · PWSID PA4110077 - Health-based Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in August 2025. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 30 times between October 2015 and October 2020. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 5 times between January 2005 and July 2009. The EPA record for these does not include a measured level. 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 25 times between May 2005 and November 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 7 times between November 2018 and October 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in September 2007. 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 once in April 2005. All have since returned to compliance, per EPA records.
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.