From ACWA: Comment Letters Needed on Draft Chromium-6 MCL Resources Available to Help Water Systems Estimate Impact

  • by BPC Staff
  • on September 18, 2013

Comment Letters Needed on Draft Chromium-6 MCL Resources Available to Help Water Systems Estimate Impact


As previously reported by ACWA, the California Department of Public Health (CDPH) released the nation’s first draft drinking water standard for chromium-6 on Aug. 22. The proposed maximum contaminant level (MCL) of 10 parts per billion (ppb) was issued as part of a complete regulatory package available here.


The 45-day public comment period on the draft MCL and regulatory package ends Oct. 11. CDPH will hold public hearings in Sacramento and Los Angeles that same day to receive comments.


CDPH officials estimate that the proposed new standard, which could be adopted as early as the end of this year, could impact about 300 community water system wells in 128 public water systems in California.  Although chromium-6 occurs throughout California at various levels, the identified wells with chromium-6 above 10 ppb are concentrated in the counties of Riverside, Los Angeles, Yolo, San Bernardino, Solano, Sacramento, Merced, Santa Barbara and Santa Cruz.  CDPH has estimated that necessary capital investments along with ongoing costs for operations and maintenance of treatment facilities in the identified areas will be $156 million annually for public water systems to comply with the proposed standard.


It is important to note that CDPH’s monitoring data does not include all of California’s water systems. CDPH has acknowledged a data gap from small water systems (i.e., those with fewer than 200 service connections). A department review of the small water system monitoring data shows that approximately 60% of those sources have not been monitored for chromium-6.


The chromium-6 work group of ACWA’s Water Quality Committee is reviewing the regulatory package and is developing comments for submission to CDPH. Though the package is still being analyzed, ACWA is particularly focused on the costs of chromium-6 treatment for California public water systems and CDPH’s estimates of the occurrence of chromium-6 statewide.


Steps to Take


ACWA is urging member agencies to prepare and submit their own comment letters to help demonstrate the impact of the MCL on public water systems. To help facilitate that process, ACWA encourages members to take the following steps:


1)      Determine how the proposed MCL affects your system. A preliminary analysis of chromium-6 occurrence data shows that 34 ACWA member agencies have reported chromium-6 detections of 10 ppb or greater. Many other agencies have detected levels under, but close to, that level.


To estimate costs associated with the draft MCL, ACWA recommends that members take advantage of an online cost estimation tool developed by Water Quality & Treatment Solutions, Inc. (WQTS) and made publicly available with financial support from the Water Research Foundation. The tool is designed to help drinking water systems estimate a range of potential costs to remove chromium-6 from their water based on system-specific information about the impacted well, water quality, and residuals handling. Additionally, members should consider other costs of meeting the MCL, including costs associated with land acquisition and/or facility modifications necessary to implement treatment technologies, the development of additional supply, and other system-specific costs.


The tool and additional information on chromium-6 treatment technologies can be found here.


2)      Draft a comment letter. Once members have determined how the draft drinking water standard would affect their systems, ACWA recommends developing and submitting a comment letter to CDPH by the Oct. 11 deadline.


ACWA is developing two templates for comment letters that will be available for members soon. One template will be for agencies with water that exceeds the draft MCL. The other will be for agencies that do not exceed the draft MCL but wish to submit comments.


The templates should be available by the first week of October.


For details on how to submit comment letters, please review CDHP’s regulatory package here.


3)      Share your comment letters with ACWA. As always, ACWA encourages members to forward their comment letters to ACWA so we can gather specific data and details on how the proposed standards would affect water agencies around the state. Letters should be forwarded to ACWA Regulatory Advocate Adam Walukiewicz at


Other Resources for ACWA Members


As previously reported, ACWA has updated its website with extensive background information on chromium-6 and a number of resources for ACWA members, including a communications toolkit with a two-page FAQ sheet as well as talking points for water agencies to use in communicating about the new draft MCL. The background materials include information about the different types of chromium and its uses, as well as the process CDPH uses in setting an MCL. The resources are available here<>.




Members with questions about the draft MCL should contact Adam Walukiewicz at<> or 916-441-4545. Members with questions about the communications toolkit should contact ACWA Communications Director Lisa Lien-Mager at<> or 916-441-4545.