MONTANA CHLORINATION RULE
This rule applies to Public Water Systems that use ground water as a source and disinfect full time with chlorine.
What are the State Regulations Governing the Montana Chlorination Rule?
The Montana Chlorination Rule is referenced in the Administrative Rules of Montana
- Reporting responsibilities are referenced in the control tests section of ARM 17.38.217
- Sampling responsibilities are referenced in the control tests section ARM 17.38.225
- Acceptable methods and levels of disinfection are referenced in the microbial treatment section of ARM 17.38.229
Which MDEQ standards apply to full time disinfection with chlorine?
Plans and specifications meeting the requirements of DEQ-1, Chapters 1 and 2 for Community Water Systems and DEQ-3, Chapters 1 and 2 of Non Community systems must be provided and approved by MDEQ, prior to installation of full-time chlorination.
When did the changes to the MT Chlorination Rule take effect?
On October 16, 2009, the Board of Environmental Review, a rule-making board formed by the Montana legislature approved changes to the Montana Chlorination Rule that were proposed by the Montana Department of Environmental Quality (MDEQ).
How has the Montana Chlorination Rule changed?
Reporting of rotated distribution system residuals is generally no longer required.
Exception: The MDEQ Public Water Supply Section may still require individual systems to monitor and report in the distribution system.
Do I still have to sample and report the chlorine residual?
Yes, systems still must sample and report entry point residuals.
What is entry point sampling?
An entry point is a sample point after chlorine treatment and before or at the first user.
Chlorine residual sampling is required at the entry point, unless a specified sample point for meeting CT calculation is identified by MDEQ. The specified sample point pertains to systems that are complying with the Groundwater Rule.
How often do I have to sample at the entry point?
Community systems sample once per day.
Nontransient noncommunity (NTNC) and Noncommunity systems (NC) sample on days water is served to the public.
How should I report on days that my system is closed?
Noncommunity systems such as restaurants and schools may not be open every day. Please note this in the data form, for example: closed, weekend, vacation.
How frequently do I report chlorine levels?
Reports are due to MDEQ on the 10th of the month following sampling.
What residual level is required?
Systems that are subject to the Montana Chlorination Rule are required to maintain a residual level of 0.2 mg/L or ppm or greater at the point of entry.
MDEQ may require a system specific residual level - see the Groundwater Rule.
What should I do if the required residual level is not maintained?
If a Public Water System was not able to maintain the required residual level due to unforeseen circumstances, please explain the circumstances in the data form, for example: equipment malfunction, repairs to system.
If the well is not being used every day, please inform us that the pump was not on.
What are the requirements for compliance?
In order for a system to be in compliance, monitoring and reporting is required on all days water is served to the public.
A minimum chlorine level of 0.2 mg/L or ppm at the entry point must be maintained in order for a system to be in compliance.
System specific residual levels may apply – Groundwater Rule.
After a violation, how do I return to compliance?
One month of maintaining the required residual level and reporting returns a system to compliance.
How will the rule change effect consecutive connections?
Monitoring and reporting requirements depend on the monitoring and reporting requirements of the wholesaler.
The following flow chart provides entry point and distribution monitoring guidance for ground water, consecutive connections and surface water systems. Disinfection Flow Chart
Are the forms available online?
Yes, click here: PWS Monitoring Forms
How can data forms be submitted?
Internet: Use the link in the upper right corner of the above form. Receipt of the form is confirmed by us.
Email: DEQChlorineReportsEmailId@mt.gov
Fax: 444-1374
Mail: Permitting and Compliance Division
1520 East 6th Ave
PO Box 200901
Helena, MT 59620-0901
For further questions, please contact?
Contact the appropriate Rule Manager for Assistance, or call DEQ PWS at (406) 444-4400.
