EDT Library and Water Quality Analyses Data and Download Page

This page contains the Electronic Data Transfer (EDT) Library, a link to Schedules for Upcoming Water Quality Monitoring, files for the Division of Drinking Water's (DDW's) water quality analyses database, and county small water system water quality data files.

Announcements: Important EDT Data Reporting Changes and Reminders

Storet Code 00618 (Nitrate as N): Reported findings are required to be in units of milligrams per liter (mg/L). California's drinking water regulations require the nitrate MCL to be expressed as "10 mg/L (as nitrogen, N)" instead of "45 mg/L (as nitrate, NO3)." The MCL has not become more stringent. Effective January 1, 2016, all nitrate data submitted to the EDT Portal must be submitted under Storet Code 00618 (Nitrate as N); otherwise the data will not be accepted. For more information, see the detailed announcement for laboratories accredited by the Environmental Laboratory Accreditation Program.

Storet Code 00620 (Nitrite as N) Effective January 1, 2016, all data submitted to the EDT Portal must be reported in units of mg/L.

Storet Code A-029 (Nitrate + Nitrite as N)
Starting January 1, 2016, all Nitrate + Nitrite data submitted to the EDT Portal must be reported in mg/L.

Laboratory Reporting Errors
Effective immediately, laboratory reporting errors will not be changed in the database. Instead, (1) The laboratory will inform the district office of the error.  (2)  District office will approve deletion of erroneous data from database, and (3)  The laboratory will resubmit data electronically.

EDT Data Submittals
EDT data submittals via email are no longer accepted.  Data are submitted via the EDT Portal webpage at: http://drinc.ca.gov/WQM/.   For more, see DDW's Announcement Regarding New Procedures for EDT (08.26.2015)  and  EDT Portal Upload Instructions (09.10.2015)

EDT Library

These executable self-extracting files* support the submittal of drinking water analytical results. More information is available at the Drinking Water Program's EDT webpage.

Write-On for Windows 95/98/2000/XP Water Quality Software Upgrade (Version 2.0r) (Zip file, expands to 4.0MB) — Last Update: September 15, 2011.

This zip file contains WO2SETUP.EXE, ~4.5 MB, the setup file for Write-On for Windows 95/98/2000/XP Water Qual7ty Input System (Version 2.0r). The file can be installed directly into an existing Write-On folder, and the changes will be made automatically. The entire installed Write-On for Windows 95/98/2000/XP software will require ~14.5 Mb of disk space with the Library installation.


Updated Software Files for Write-On (Zip) - Last Update: September 30, 2016

This zipped file contains 3 files and will expand to ~70 kB. These updates contains a revised form, and a revised file that contains updated storet information. These files are designed to be used with the Write-On software, and should be unzipped and placed in the \WOWIN2 folder..

Water System and Source Libraries (Zip file, expands to 4MB) — Last Update: September 18, 2019

This zipped file contains 47 files and will expand to ~4 MB. These system and source files are designed to be used with the Write-On software, and should be unzipped and installed in the \WOWIN2 folder. It includes both large and small water system sources, and an updated laboratory data file.

List of Water Quality Chemicals and Parameters (Excel) — Last Update: May 29, 2019.

This is an MS Excel file (~70 kB) that lists chemicals in Write-On, and includes US EPA STORET numbers or other identifiers, maximum contaminant levels, detection levels for purposes of reporting, and reporting units.

Hardcopy Reporting Forms (Zip) — Last Update: January 22, 2018.

This file, FORMS.ZIP, 67 kB, is self-extracting (expanding to 657 kB) and includes the following forms in MS Word: (1) Base Neutral and Acids, (2) Organic Chemical Analysis, (3) Radioactivity Analysis, and (4) General Mineral, Physical & Inorganic Chemical Analyses. NOTE: These forms are for hardcopy submission of water quality data only (prior to the requirement for EDT submittal) and not for the required submittal of data by EDT.

Write-On Library Mover (Zip) — Last Update: March 25, 2003

This zip file contains the Write-On Library Mover (LIBMOVE.EXE) is a utility that assists you in moving updated system and source libraries to your hard disk drive. It is ~15 kB in size. This file saves you the task of having to reenter the sources and systems you created to the new libraries with Library Maintenance. This file was formerly included with the Water System and Source Libraries (ALL_LIB.EXE). Included is a Library Mover.doc 03/25/2003

*Obtain a copy of these files by clicking on the highlighted text to download a self-extracting version of these files. After successful download, simply double click on the file in your File Manager and the extraction process will be performed.


DDW's drinking water quality monitoring notification documents identify upcoming required contaminant testing of drinking water for water systems in California. They are updated periodically to reflect changes in the database.

Monitoring Schedules


The following historical water quality analyses data are available to download and are divided among four .dbf files (Chemical.zip, Chemhist.zip, Chemarch.zip and Chemxarc.zip), four supporting data files (Siteloc.zip, Watsys.zip, Lab.zip, and Storet.zip, and one Word file that provides explanation.

It is recommended you use WinZip software program to extract the downloaded water quality data files if you receive an error message using any other program.

NOTE: The zipped files must be copied to your drive and expanded. After expansion, the .DBF file can be imported into most well know database software programs, such as Microsoft Access, Fox Pro, or Paradox. Note that spreadsheet programs such as Excel are not able to import all of the records in the database and should not be used to prepare reports.

NOTICE TO USERS OF THE DATABASE: Users of this database should use care in interpreting these data. For example, a single detection of a contaminant may not indicate contamination. DDW would not consider a single detection of a contaminant, if unconfirmed with a follow-up detection, to be an actual finding. As another example, the presence of a contaminant in raw water at a given concentration does not necessarily mean that the water was served by the water system to its customers, or, if served, that the contaminant was present at that concentration. Water systems may not use certain sources or may treat or blend them prior to service.

Questions about contaminants in particular sources are best addressed by the specific public water system, or by the DDW district office.

Drinking water analyses reported directly from laboratories - Last Update September 15, 2019.

  • CHEMICAL.ZIP contains chemical data from January 1, 2013 through this month
  • CHEMHIST.ZIP contains chemical data from January 1, 2007 through December 31, 2012
  • CHEMARCH.ZIP contains chemical data from January 1, 2000 through December 31, 2006
  • CHEMXARC.ZIP contains chemical data from April 1974 through December 31, 1999

Supporting database files - Last Update September 15, 2019.

EDT Information

EDT Data Submittal - FAQ
EDT - Main Page

Information about Chemicals and Contaminants

Chemicals and Contaminants in Drinking Water

Schedules of Upcoming Monitoring

Monitoring Schedules

More Information

Drinking Water Statutes and Regulations
Division of Drinking Water

Additional Information for Laboratories

Additional Information for Laboratories