Drinking Water Proposed Disinfection Requirements Rule (DRR)
The proposed Drinking Water Disinfection Requirements Rule was published in the PA Bulletin on February 20, 2016 with a 60-day comment period (ending April 19, 2016).
Below are links to the proposed rule:
PA Bulletin PDF
Overview of the Disinfection Requirements Rule (DRR)
The proposed rule includes the following:
Changes to disinfection requirements at both the entry point and within the distribution system are being proposed.
A clarification that the minimum entry point residual for surface water and GUDI systems is 0.20mg/L.
Increased disinfectant residual requirements in the distribution system from 0.02 mg/L to 0.2 mg/L at all points in the distribution system. Monitoring must be conducted on a weekly basis as per a sample siting plan.
New monitoring and reporting requirements for surface water and groundwater under the direct influence of surface water (GUDI) systems regarding the calculation and reporting of CT/log inactivation values.
New requirements for a nitrification control plan for systems that use chloramines.
In addition, the proposed rule includes minor changes to the Stage 2 Disinfectants/Disinfection Byproducts Rule, Long Term 2 Enhanced Surface Water Treatment Rule and the Lead and Copper Rule Short-Term Revisions to obtain or maintain primacy.
Background on Disinfection Residual Requirement in the Distribution System
DEP's advisory committee, the Small Water Systems Technical Assistance Center Board (TAC) presented their concerns on a number of provisions. One in particular was the proposed limit of 0.2 mg/L (free or total chlorine) in the distribution system. Concerns noted were whether or not the new level was necessary given no public health threat and with no public health benefit, no cost/ benefit analysis, additional O&M and BMPs, and increased compliance costs. The TAC Board voted on and made the recommendation to change the proposed minimum required disinfectant residual in the distribution system to 0.1 mg/L for both free and total chlorine, 95% of the time. Additional discussions centered on taste and odor complaints due to enhanced chlorine levels, and the need for system wide elevations of chlorine levels when many of the identified water-borne problems have been premise-specific.
DEP has a dedicated page on their website with a history of the proposed rule. Visit dep.pa.gov and select Business, Water, Bureau of Safe Drinking Water, Drinking Water Management, Regulations.