Information for Public Drinking Water Systems
The Division of Drinking Water (DDW) regulates public water systems; oversees water recycling projects; permits water treatment devices; supports and promotes water system security; and performs a number of other functions. For more about DDW activities, click on a link below.
The Division of Financial Assistance provides funding opportunities for drinking water system improvements; provides support for small water systems and for improving technical, managerial, and financial (TMF) capacity; and certifies drinking water treatment and distribution operators.
Private domestic wells are not regulated by DDW; the GAMA Program has information pertinent to private domestic well water quality.
Announcements
For recent announcements, please see the Division of Drinking Water’s webpage.
To receive email notices about upcoming drinking water regulations and other drinking water-related information, subscribe to our email lists (Click on the “Drinking Water” section).
General Information
Assessment and Protection Programs
- DDW's Drinking Water Source Assessment and Protection (DWSAP) Program
- DPR's Ground Water Protection Program
- DPR's Surface Water Protection Program
Backflow Prevention Devices/Cross-Connection Control
Biological Treatment Systems for Nitrate Removal
Consolidation Information
Drought-Related Information
Funding-Related Information
Laboratory Data Portal
Lead and Copper Rule
Monitoring
- Electronic Data Transfer (EDT) for Laboratory Results
- Contaminants in Drinking Water
- Public Water System Monitoring Schedules
- Water Quality Data
Notification
Paperless Office System
Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS)
- General Order Requiring Monitoring for PFAS in Drinking Water Sources
- Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS)
- Frequently Asked Questions: Per- and Poly-fluoroalkyl Substances (PFAS)Water Monitoring
- Example PFOA/PFOS Notification Letter: (PDF) (Word)
- Laboratories Accredited to Analyze for PFAs in Drinking Water by EPA Method 537 Revision 1.1 or EPA Method 537.1
- Drinking Water Sample Collection for PER and POLYFLUORINATED ALKYL SUBSTANCES (PFAS) Sampling Guidance
Permits for Herbicides to Control Aquatic Plants (SWRCB)
Permits and Regulated Activities
- Permit Information
- Fluoridation (includes April 2015 Revision to Optimal Fluoride Level)
- Water Treatment and Distribution System Operator Certification
Point of Entry and Point of Use Treatment
Public Water Systems
- Legal Definitions
- Classification Decision Tree (PDF)
- Drinking Water Supply Service Area Look-Up Tool
Recycled Water
Regulations
Reports and Publications
- DDW Reports and Publications
- Annual Capacity Development Report
- Annual Compliance Report
- Water Separation Criteria
Security and Emergencies
SWS Guidance
- NaOCL Examples
- Continuous Chlorination Disinfection System Operation, Maintenance & Monitoring Guidance for Small Water Systems
- Continuous Chlorination Disinfection System: Design, Installation & Configuration Guidance for Small Water Systems
Total Coliform Rule
US EPA's Public Drinking Water Systems Programs
Water System Administrators