Letter to Public Water Suppliers concerning new perchlorate regulations
Date: September 15, 2006
RE: New Perchlorate Regulations
Dear Public Water Supplier:
This letter is to notify you of changes to MassDEP Drinking Water regulations (310 CMR 22.00) promulgated
on July 28, 2006 regarding the establishment of a maximum contaminant level (MCL) for perchlorate and the
associated compliance monitoring requirements. The attached fact sheet provides questions and answers
regarding the new perchlorate regulations. You should receive a revised sampling schedule and information
regarding training on the new regulations by November 1, 2006. If you have not received a revised sampling
schedule by November 1, please contact your regional office of MassDEP to request one. You may obtain
an electronic copy of the revised regulations at the following MassDEP web page:
http://www.mass.gov/eea/agencies/massdep/water/regulations/regulations-and-standard.html.
Please be aware that as a Community (COM) or Non-Transient-Non-Community (NTNC) Public Water
System you are responsible for meeting the following requirements:

 New Maximum Contaminant Level (MCL): The regulation changes establish a MCL of 0.0020
milligrams per liter (mg/L) for perchlorate.

 Monitoring Requirements: The monitoring requirements for perchlorate are outlined below. Note
that samples collected in 2004 may be an acceptable substitute for this monitoring. However,
regardless of the amount of historic sample results, all systems will be required to collect at least
one sample round per year beginning with the 2007 calendar year.
o Initial Monitoring for Groundwater Sources: All COM and NTNC systems served by
groundwater shall monitor for perchlorate once during the month of April 2007 and once
during the month of September 2007.
o Initial Monitoring for Surface Water Sources: Those COM and NTNC systems served by
surface water shall monitor for perchlorate for four consecutive quarters beginning with
the first quarter of 2007 (starting January 1, 2007).
o Routine Monitoring for all Sources: The frequency of routine monitoring will depend on the
results of the initial monitoring.
o Monitoring Waivers: Systems will not be eligible for Monitoring Waivers until the next
compliance monitoring period (2008-2010). MassDEP will provide waiver applications for
the 2008-2010 monitoring period in the fall of 2007.
 Analytical Laboratory Requirements: All compliance monitoring samples for perchlorate shall be
collected using sterile sampling techniques. All samples must be analyzed by a laboratory that is
approved by MassDEP to test for perchlorate in drinking water. Approved laboratories will provide
sterile sample bottles, filters, and collection instructions. For a list of MassDEP approved labs go
to http://www.mass.gov/eea/agencies/massdep/water/drinking/approved-perchlorate-laboratoriesand-related-informati.html and select the document under the heading "List of DEP-Approved
Perchlorate Laboratories." MassDEP is moving to amend the laboratory certification regulations to
formally certify for the analysis of perchlorate. Until then, laboratories that are listed as MassDEPapproved for perchlorate analysis will not be listed on our On-Line Searchable Laboratory
Certification Listing web page.
See our perchlorate web page at http://www.mass.gov/eea/agencies/massdep/water/drinking/perchlorateinformation.html for additional information on perchlorate, including Best Environmental Management
Practices (BMPs) recommended for fireworks displays and blasting operations.

 If you have any questions regarding this letter, please contact Joe Cerutti by email at
joseph.cerutti@state.ma.us or by phone at (617) 292-5859.
Very truly yours,
Damon Guterman
Acting Program Director
MassDEP, Drinking Water Program