To: Members of the Castle Rock Water Commission
From: Mark Marlowe, P.E., Director of Castle Rock Water
Matt Benak, P.E., Water Resources Manager
Title
Update on State’s Direct Potable Reuse Regulations
Town Council Agenda Date: NA
Body
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Executive Summary
The State of Colorado expects to double its population by 2050 which will create significant added demands on the limited supplies of our water resources. The Colorado Water Plan delineates a variety of strategies to help address the projected gaps in supply versus demand, and one of those strategies is Direct Potable Reuse (DPR). DPR is defined as the use of a series of water treatment processes that produce purified finished drinking water utilizing a source containing treated wastewater that has not passed through an environmental buffer. Currently, Castle Rock Water (CRW) practices Indirect Potable Reuse (IPR) where reusable water is diverted off of Plum Creek, approximately six miles downstream of the Plum Creek Water Reclamation Authority plant outfall, and is then pumped back to the Plum Creek Water Purification Facility (PCWPF) for treatment and subsequent delivery to our customers. CRW is currently working with a professional engineering consulting firm (CDM-Smith) on a cost-benefit and risk assessment study to evaluate DPR for the Town.
The Colorado Department of Public Health and Environment (CDPHE) has developed a new rule within the Colorado Primary Drinking Water Regulations (Regulation No. 11, Chapter 14) clearly outlining the steps water treatment providers would need to follow to gain approval of a DPR system. These steps include: extensive public outreach; installation of advanced water purification processes; wastewater system monitoring and management; and enhanced monitoring and reporting.
CRW, along with many other water providers, industry experts, university researchers, and staff from CPDHE (along with input from the EPA), helped to formulate the DPR rule over the past several years. On October 11, 2022, the Water Quality Control Commission (WACC) formally considered the rule presented by CPDHE staff. Matt Benak (CRW Water Resources Manager), along with other interested stakeholders also spoke in support of the rule. The WQCC voted to adopted the rule (along with some minor errata that will be made to the final rule) at the upcoming November meeting. The rule will formally go into effect in the first quarter of 2023.
The Water Quality Control Commission is the administrative agency responsible for developing specific water quality policy in Colorado, in a manner that implements the broader policies set forth by the Legislature in the Colorado Water Quality Control Act. The WQCC adopts water quality classifications and standards for waters of the state, as well as various regulations aimed at achieving compliance with those classifications and standards.