Public water system · FL2100610
ActiveKeystone Postmaster Grid
At a glance
Keystone Postmaster Grid (PWSID FL2100610) is an active community water system in Clay County, Florida. It reports serving 5,092 people through 1,845 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 5 violations for this system; none is health-based, and the most recent began in January 2001.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
5,092
Service connections
1,845
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Keystone Postmaster Grid compare with other water systems in Clay County?
By EPA's size categories, Keystone Postmaster Grid is a medium system (3,301 to 10,000 people). Clay County has 77 active public water systems, and Keystone Postmaster Grid is the 5th-largest of them by population served. Its population served is about twice the county average of 2,409 people per system, and accounts for 2.7% of the 185,520 people reported by systems filed under the county. Across Florida, the 5,197 active systems average 4,345 people each. Nationally, the average active community water system reports serving 6,703 people, so Keystone Postmaster Grid is about 24% below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Florida has 1,640 active community water systems, 32% of the state's 5,197 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 4,996 Florida systems (96%) list groundwater as their primary source.
Who owns and regulates Keystone Postmaster Grid?
EPA lists Keystone Postmaster Grid as privately owned. The FL state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 57 of the 77 active systems in Clay County (74%) are also privately owned.
Does Keystone Postmaster Grid have drinking water violations?
EPA's records list 5 violations for this system; none is health-based, and the most recent began in January 2001. The violations listed here began between October 1984 and January 2001. By type: 5 monitoring and reporting. The contaminants or rules involved are Total coliform bacteria (TCR), Toxaphene, Methoxychlor and Endrin. EPA lists 5 as archived. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2001-01-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1984-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Toxaphenecode 2020 | No | Archived |
| 1984-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Methoxychlorcode 2015 | No | Archived |
| 1984-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Endrincode 2005 | No | Archived |
| 1984-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Lindane (gamma-BHC)code 2010 | No | Archived |
All 5 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Keystone Postmaster Grid: frequently asked questions
Who runs Keystone Postmaster Grid?
Keystone Postmaster Grid (PWSID FL2100610) is a community water system privately owned. It is regulated by the FL state drinking water program.
How many people does Keystone Postmaster Grid serve?
Keystone Postmaster Grid reports serving 5,092 people through 1,845 service connections in Clay County, Florida.
Where does Keystone Postmaster Grid get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Keystone Postmaster Grid have any drinking water violations?
EPA's records list 5 violations for this system; none is health-based, and the most recent began in January 2001. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Keystone Postmaster Grid's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 5 violations for this system; none is health-based, and the most recent began in January 2001. For current results, consult the system's annual water quality report, EPA ECHO, or the FL state drinking water program.
Where can I find Keystone Postmaster Grid's water quality report?
As a community water system, Keystone Postmaster Grid must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Clay County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Orange Park Grid | Clay | 127,904 | Community | Groundwater |
| Lake Asbury Grid | Clay | 27,001 | Community | Groundwater |
| Town of Orange Park | Clay | 8,668 | Community | Groundwater |
| City of Green Cove Springs WTP | Clay | 7,000 | Community | Groundwater |
| Wilkinson Schools | Clay | 1,822 | Non-transient non-community | Groundwater |
| St. Johns Landing Apartments | Clay | 1,310 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Keystone Postmaster Grid, PWSID FL2100610, Florida”, https://aquacensus.com/water-systems/florida/keystone-postmaster-grid-fl2100610 (data as of October 1, 2026).