Independent screening of EPA drinking-water records for potential data-quality inconsistencies.
This tool examines EPA drinking-water records to identify potential date inconsistencies that may warrant further review.
Reversed-date findings: Records where a reported period end date precedes its start date.
Historical-date warnings: Records containing dates before 1950. Some may reflect legacy placeholders rather than errors.
How agencies can use these results: Search by Water System ID, review individual findings, and download CSV reports for comparison against authoritative source records.
This is an independent data-quality screening tool. Findings are not verified errors and do not establish regulatory noncompliance.
57,446 unique violations flagged across both reports.
444 violations appear in both categories and are counted only once in the combined total.
Showing a preview across all water systems. Search to view one system's findings.
Download Date Findings CSV Download Historical Warnings CSV| Water System | Violation | Check | Start | End |
|---|---|---|---|---|
| MD1040016 | 9610001 | NON_COMPL_PER_BEGIN_DATE | 01/01/1993 | 08/01/1912 |
| AL0000393 | 5703 | NON_COMPL_PER_BEGIN_DATE | 10/11/2002 | 08/11/2002 |
| MD1160012 | 95V0001 | NON_COMPL_PER_BEGIN_DATE | 01/01/1995 | 01/01/1910 |
| MD1160012 | 94V0002 | NON_COMPL_PER_BEGIN_DATE | 07/01/1993 | 01/01/1910 |
| MD1160012 | 96V0003 | NON_COMPL_PER_BEGIN_DATE | 01/01/1993 | 01/01/1910 |
| MD1160012 | 96V0005 | NON_COMPL_PER_BEGIN_DATE | 01/01/1993 | 01/01/1910 |
| MD1160012 | 96V0006 | NON_COMPL_PER_BEGIN_DATE | 01/01/1993 | 01/01/1910 |
| MD1160012 | 9610003 | NON_COMPL_PER_BEGIN_DATE | 01/01/1993 | 01/01/1910 |
| MD1160012 | 95V0002 | NON_COMPL_PER_BEGIN_DATE | 07/01/1995 | 01/01/1910 |
| MD1190008 | 9811687 | NON_COMPL_PER_BEGIN_DATE | 04/01/1998 | 02/01/1998 |
| MD1160012 | 96V0001 | NON_COMPL_PER_BEGIN_DATE | 10/01/1995 | 01/01/1910 |
| MD1030056 | 94V0001 | NON_COMPL_PER_BEGIN_DATE | 01/01/1994 | 11/01/1911 |
| MD1030056 | 94V0002 | NON_COMPL_PER_BEGIN_DATE | 07/01/1993 | 11/01/1911 |
| MD1030056 | 9610004 | NON_COMPL_PER_BEGIN_DATE | 07/01/1995 | 11/01/1911 |
| MD1030056 | 9812421 | NON_COMPL_PER_BEGIN_DATE | 07/01/1997 | 11/01/1911 |
| MD1040016 | 91V0002 | NON_COMPL_PER_BEGIN_DATE | 09/01/1991 | 08/01/1912 |
| MD1040016 | 91V0001 | NON_COMPL_PER_BEGIN_DATE | 09/01/1991 | 08/01/1912 |
| MD1030056 | 95V0001 | NON_COMPL_PER_BEGIN_DATE | 04/01/1995 | 11/01/1911 |
| NC0239483 | 4625309 | NON_COMPL_PER_BEGIN_DATE | 06/29/2014 | 06/27/2014 |
| OR4194852 | 2746592 | NON_COMPL_PER_BEGIN_DATE | 12/01/1992 | 08/10/1992 |
| Water System | Violation | Compliance Begin | Compliance End | Noncompliance Begin | Noncompliance End |
|---|---|---|---|---|---|
| MD1040016 | 9610001 | 01/01/1993 | 12/31/1995 | 01/01/1993 | 08/01/1912 |
| MD1160012 | 95V0001 | 01/01/1995 | 03/31/1995 | 01/01/1995 | 01/01/1910 |
| MD1160012 | 94V0002 | 07/01/1993 | 04/28/1995 | 07/01/1993 | 01/01/1910 |
| MD1160012 | 96V0003 | 01/01/1993 | 12/31/1995 | 01/01/1993 | 01/01/1910 |
| MD1160012 | 96V0005 | 01/01/1993 | 12/31/1995 | 01/01/1993 | 01/01/1910 |
| MD1160012 | 96V0006 | 01/01/1993 | 12/31/1995 | 01/01/1993 | 01/01/1910 |
| MD1160012 | 9610003 | 01/01/1993 | 12/31/1995 | 01/01/1993 | 01/01/1910 |
| MD1160012 | 95V0002 | 07/01/1995 | 07/31/1995 | 07/01/1995 | 01/01/1910 |
| MD1160012 | 96V0001 | 10/01/1995 | 12/31/1995 | 10/01/1995 | 01/01/1910 |
| MD1030056 | 94V0001 | 01/01/1994 | 03/31/1997 | 01/01/1994 | 11/01/1911 |
| MD1030056 | 94V0002 | 07/01/1993 | 08/05/1996 | 07/01/1993 | 11/01/1911 |
| MD1030056 | 9610004 | 07/01/1995 | 12/31/1995 | 07/01/1995 | 11/01/1911 |
| MD1030056 | 9812421 | 07/01/1997 | 10/20/1998 | 07/01/1997 | 11/01/1911 |
| MD1040016 | 91V0002 | 09/01/1991 | 11/30/1991 | 09/01/1991 | 08/01/1912 |
| MD1040016 | 91V0001 | 09/01/1991 | 09/30/1991 | 09/01/1991 | 08/01/1912 |
| MD1030056 | 95V0001 | 04/01/1995 | 06/30/1995 | 04/01/1995 | 11/01/1911 |
| VT0005072 | 647798 | 10/01/1900 | 10/31/1900 | 10/01/1900 | 10/31/1900 |
| VT0005072 | 689198 | 04/01/1900 | 04/30/1900 | 04/01/1900 | 04/30/1900 |
| VT0005072 | 698298 | 07/01/1900 | 07/31/1900 | 07/01/1900 | 07/31/1900 |
| VT0005072 | 699398 | 07/01/1900 | 07/31/1900 | 07/01/1900 | 07/31/1900 |
Showing up to 20 findings per category. Download CSV reports for complete results. Findings require review and do not establish regulatory noncompliance.