colorado water quality data

Annual Data Call: Use CDSN to submit your data.

CDSN conducts joint Data Calls annually with CDPHE and the Water Quality Control Division to make it easy for you to submit your data directly from AWQMS, without reformatting. No need to double submit data for submission to WQCD for Data Calls or Reg85. WQCD has determined that it is more efficient for WQCD to receive your data through CDSN.

CDSN submitted over 180,000 results for 22 data partners to CDPHE for the most recent data calls for Regulations 34, 35, and 38.
The CDPHE Environmental Data Unit which collects data for the Water Quality Control Division (WQCD)has partnered with the Colorado Data Sharing Network (CDSN) for over 10 consecutive years to facilitate water data submissions directly from CDSN. Organizations with water data that are already uploading water data meeting the WQCD guidelines do not have to individually reformat and resubmit their data to WQCD if they are responding to a CDPHE data call. This joint effort between CDSN and CDPHE WQCD has been very efficient for the data providers and has increased data call responses. Over 780,000 Colorado nutrient and baseline water quality results have been uploaded to CDSN in the last 5 years!
More information about the division's data calls, triennial reviews and schedule for Regulations 31-38 can be found [here]. The latest schedule for data gathering and assement is found in Table 3 of the Division's Section 303(d) Listing Methodology 2020 Listing Cycle document [here].
There will be a data call for Regulations 32 & 36 - The Arkansas and Rio Grande Basins due September 15, 2021.
The Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division (WQCD;"division") typically makes an annual request for recent surface water quality data parameters including biological, physical, chemical, and other related data. Rotating annual data requests between specific watershed basins allows the division to focus its resources in preparation for specific basin standards rulemaking hearings. The annual "data call" requests follow the CDPHE triennial rulemaking hearing schedule.
CDSN works with Colorado Department of Public Health and Environment, Water Quality Control Division to submit data uploaded into the CDSN for the division's request for surface water quality data directly from CDSN. When the division is requesting data collected during a specified period, CDSN works with data partners that have relevant data in the CDSN data management system to identify and submit any data that the data owner wishes to provide to CDPHE.
While Regulation 85 nutrient monitoring data calls have an April 15 deadline, CDPHE is now implementing September 15 deadlines for stream data for triennial basin reviews and data that will be used in the 303(d) assessments. Typically CDPHE and CDSN will post a data call notice describing the data of interest to CDPHE each June.  CDSN will begin pulling the data to be submitted out of CDSN's database on September 1 and will provide each data provider with information showing that it was submitted on or before September 15 to WQCD on your behalf.
Colorado’s 303(d) listing methodology provides a framework for determining attainment or nonattainment of assigned numeric water quality standards and designated uses. The 303(d) listing methodology is reviewed and updated every two years in anticipation of 303(d) List and Monitoring and Evaluation (M&,E) List Development. 2020 303(d) listing methodology. The latest schedule for data gathering and assement as recently revised by the Division from  Table 3 in   Section 303(d) Listing Methodology 2020 Listing Cycle document.  The most recent data call schedule provided by CDPHE WQCD (April 2021) is below:
 The division receives data submissions directly from CDSN. Data has to be uploaded before the first day of the month the data is due, in order to be submitted by the division’s deadline. If you use CDSN you will not need to use the division’s data template(s). CDSN’s WQX-compatible data management system can upload a copy of your data directly to the Water Quality Portal/WQX (if desired) with no extra effort. CDSN provides efficient and accurate data formatting and upload services for a reasonable fee, which supports the costs of hosting and maintaining the robust CDSN data management system and tool kit.
CDSN technical assistance can be reached via email at and at 970 . 258 . 0836. We look forward to working with you!

Steps to take for CDSN to submit your data contained in CDSN on your behalf for a WQCD Data Call: You MUST do ALL of the following--

  • ALL Data Organizations (ESTABLISHED & NEW CDSN Data Organizations): Notify CDSN ( | 970 . 258 . 0836) and WQCD EDU ( in writing via email of:
    • Your intent to participate through CDSN no later than three months before the CDPHE data submittal deadline -AND- notify the Water Quality Control Division at least 45 days before the deadline; and
    • Which data you want CDSN to submit to WQCD (date range, parameters (analytes), and specific monitoring locations by ID or their HUC 8 codes).
  • Identify to CDSN in writing if your data has been prior submitted to WQCD for REG85 or any other regulation (31-38, etc).
  • Commit to having your data upload complete with all of the WQCD required minimum data elements, including Sample Fraction, into CDSN fifteen days prior to the submission deadline. (Contact CDSN if you need help uploading your data).


For any new data organization that wants to begin uploading data for the first time into CDSN you must contact CDSN no later than three months before the CDPHE submission deadline and request to join the CDSN with the understanding that your submission data must be uploaded by at least 15 days prior to the data submission deadline. CDSN will work first come-first served with NEW DATA ORGANIZATIONS to find a customized expedited pathway to get your data formatted and uploaded in time for the data submission deadline. For example, if the deadline is September 15, then data organizations start working with CDSN by June 15, notify the Water Quality Control Division of their intention to submit data via the CDSN by August 1, and commit to having their data uploaded by September 1.