The Stage 2 Disinfection Byproducts Rule (DBPR) was promulgated in January 2006 and applies to all community and non-transient non-community (NTNC) water systems that add a primary or residual disinfectant other than ultraviolet light (UV) or deliver water that has been treated with a primary or residual disinfectant other than UV. Systems that purchase disinfected water are included in this rule.
The Stage 2 DBPR builds on the existing Stage 1 DBPR and provides increased health protection. Stage 1 monitoring will end when Stage 2 monitoring begins. Important deadlines are summarized in the following table:
Table 1. Stage 2 DBP Rule Deadlines
| Public Water Systems |
Actions and Deadlines |
| Schedule number |
Submit IDSE standard monitoring plan, system specific study plan or 40/30 certification |
Complete an initial distribution system evaluation (IDSE) |
Submit IDSE report |
Begin Stage 2 compliance monitoring |
| CWS = Community Water Systems. NTNCWS = Non-Transient Non-Community Water Systems. |
| State may grant up to an additional two years for systems making capital improvements. |
| * Systems under 10,000 population that have to monitor for Cryptosporidium may begin Stage 2 compliance monitoring October 1, 2014. |
CWS and NTNCWS serving
at least 100,000 |
1 |
10/1/2006 |
9/30/2008 |
1/1/2009 |
4/1/2012 |
| CWS and NTNCWS serving 50,000 ‑ 99,999 |
2 |
4/1/2007 |
3/31/2009 |
7/1/2009 |
10/1/2012 |
| CWS and NTNCWS serving 10,000 ‑ 49,999 |
3 |
10/1/2007 |
9/30/2009 |
1/1/2010 |
10/1/2013 |
| CWS serving fewer than 10,000 |
4 |
4/1/2008 |
3/31/2010 |
7/1/2010 |
10/1/2013* |
| NTNCWS serving fewer than 10,000 |
4 |
N/A |
N/A |
N/A |
10/1/2013* |
Stage 2 DBPR Information
Additional Resources
See the following for more Stage 2 DBPR information: