Protecting Public Health and the Environment.

Revised Total Coliform Rule

Idaho adopted the federal Revised Total Coliform Rule (RTCR), which went into effect April 1, 2016. The RTCR replaced the 1989 Total Coliform Rule and applies to all regulated public drinking water systems. The RTCR removed the maximum contaminant level (MCL) for total coliform and established an MCL for E. coli. The RTCR uses E. coli and total coliform positive results to initiate a “find and fix” approach through performing assessments to address pathways where potential pathogens could enter the distribution system. The rule also outlines start-up procedures and changes to monitoring requirements for seasonally operated systems.

Key Provisions

  • The new rule began April 1, 2016, for all systems
  • Requires performing assessments and taking corrective actions
  • Changed bacteria MCLs (added E. coli, removed total coliform)
  • Requires updating or revising sample siting plans
  • Changed monitoring requirements for small systems
  • Requires start-up procedures for seasonal systems

General Monitoring Information

  • All public water systems transitioned to the new rule on their existing total coliform schedule.
  • The same number of routine total coliform samples are required for all systems.
  • Systems using surface water or ground water under the direct influence of surface water remain on the same total coliform schedule.
  • Systems that serve over 1,000 people remain on the same total coliform schedule.
  • Repeat total coliform samples are required within 24 hours of notification of a routine total coliform positive sample.
  • Three repeat total coliform samples are required for each routine total coliform positive sample.
  • DEQ cannot waive the requirements for repeat total coliform samples.
  • Ground water systems are still required to take triggered total coliform source samples after a routine positive coliform sample.
  • Systems with monthly total coliform monitoring schedules return to routine sampling the month following a total coliform positive sample (the RTCR does not require 5 routine samples the month following a positive sample).
  • Systems with quarterly total coliform monitoring schedules must take 3 routine samples the month following a coliform positive result.

Sample Siting Plans

Sample siting plans were required under the original Total Coliform Rule and all system owners were required to review and update their sample siting plans by April 1, 2016. Owners and operators are not required to turn these plans in to DEQ; however, seasonal system owners that are conducting monthly total coliform monitoring and that want to qualify for quarterly monitoring must submit their plans for approval. Sample siting plans will be reviewed during sanitary surveys and during any site visits or assessments performed by DEQ.

  • The plan must identify routine and repeat total coliform sampling locations representative of the distribution system.
  • Repeat total coliform sampling locations include the original location, a tap within 5 connections upstream, and a tap within 5 connections downstream.
  • Ground water system owners must identify all sources for ground water triggered source total coliform sampling required after a positive total coliform sample. Owners of ground water systems that serve 1,000 or fewer people and with only one well may substitute the source sample for either the upstream or downstream repeat sample if approved by DEQ in writing.
  • Samples can be taken from a customer’s premise, dedicated sampling station, or other designated compliance sampling site.
  • Seasonal system owners must identify in the plan the most vulnerable period (highest demand/wet weather).

Small Public Water System Monitoring

Systems that use only ground water and serve 1,000 or fewer people are allowed to be on reduced (or quarterly) total coliform monitoring.

Noncommunity Public Water Systems

Noncommunity systems that are not seasonal may remain on quarterly monitoring unless the following occur:

  • A Level 2 Assessment is triggered.
  • Any treatment technique violation such as the failure to conduct an assessment or to take corrective actions in the time frame specified.
  • Two RTCR total coliform monitoring violations or one RTCR E. coli monitoring violation and two Level 1 Assessments in a rolling 12-month period.

DEQ may reduce a noncommunity system’s total coliform monitoring schedule from monthly to quarterly if the reason for the increased monitoring is resolved and the system meets all of the following:

  • A sanitary survey was completed by DEQ with no significant deficiencies identified OR a Level 2 Assessment from a qualified party is completed and the system is free of sanitary defects and has a protected water source, and
  • Has a clean compliance history for the past 12 months, which means no MCL violations for total coliform (1989 rule) or E. coli, no monitoring violations for total coliform or E. coli, and no Level 1 or Level 2 Assessment triggers.
Community Public Water Systems

Small community systems that serve only ground water may qualify for quarterly monitoring if the system meets all the following:

  • Is in compliance with the responsible charge operator requirements.
  • Has a clean compliance history for the past 12 months, which means no MCL violations for total coliform (1989 rule) or E. coli, no monitoring violations for total coliform or E. coli, and no Level 1 or Level 2 Assessment triggers.
  • The most recent sanitary survey shows no significant deficiencies/sanitary defects, or is in compliance with a plan to correct the significant deficiency. If a significant deficiency still exists and is a concern for contamination, DEQ may not approve quarterly monitoring until the deficiency is corrected.
  • The system has a protected water source and meets construction standards. This does not mean the system owner has to upgrade to meet today’s construction standards but that the system owner has made no unapproved material modifications or expansions, Material modifications or expansions made without DEQ approval are violations of Idaho Code Title 39-118.
  • The system must have one or more of the following:
    • A site visit by the state within the past year equivalent to a Level 2 Assessment or a Level 2 Assessment was performed and all sanitary defects were corrected on or a plan to correct.
    • An approved cross connection control program.
    • Continuous disinfection entering the distribution system with state specified residuals.
    • Demonstrated 4-log removal or inactivation of viruses provided under the Ground Water Rule.

A small community system on quarterly monitoring will be placed on monthly monitoring the month after any of the following occur:

  • A Level 2 Assessment is triggered.
  • Failure to conduct an assessment or to take corrective actions in the time frame specified.
  • Any treatment technique violation such as the failure to conduct an assessment or to take corrective actions in the time frame specified.
  • Two RTCR monitoring violations in a rolling 12-month period.

Assessments

Assessments are intended to identify and address any potential sanitary defects that may allow contamination into the distribution system. Assessments must be performed as soon as practical after the triggered event and must be submitted to DEQ within 30 days. DEQ provides Level 1 and Level 2 Assessment forms.

Sanitary defects are pathways of entry for microbial contamination into the distribution system or that indicate a failure or imminent failure in a barrier that is already in place. Examples include loss of pressure, cross connections between potable and nonpotable water, treatment failure, deterioration or defective components, or water main leaks or breaks.

A public water system owner or operator may consult with DEQ staff at any time during the assessment process.

Level 1 Assessments

The monthly MCL under the 1989 rule for total coliform is replaced by Level 1 Assessment. A Level 1 Assessment can be performed by a system owner or operator and no special license is required, but the person conducting the assessment should be familiar with the system. Level 1 Assessments are triggered when the following occur:

  • For system operators taking 40 or more samples per month, the sample results exceed 5.0% total coliform positive (not E. coli) samples for the month.
  • For system operators taking less than 40 samples per month, two or more sample results that are total coliform (not E. coli) positive.
  • The owner or operator fails to take the required number of repeat samples.
Level 2 Assessments

Level 2 Assessments are in response to E. coli positive samples or continued total coliform results and are intended to be more in-depth than a Level 1 Assessment. A Level 2 Assessment can be performed by a distribution or treatment licensed operator as long as they are licensed at the level of the system classification or higher. A licensed professional engineer with experience in drinking water can also perform a Level 2 Assessment. DEQ or the Health District will perform Level 2 Assessments associated with E. coli related triggers. Level 2 Assessments are triggered when the following occur:

  • There is an E. coli positive routine sample followed by a total coliform positive repeat sample or a total coliform positive routine sample followed by an E. coli positive repeat sample.
  • The system owner or operator fails to take any or all of the required repeats following an E. coli positive routine sample.
  • There are two or more Level 1 triggers in a rolling 12-month period. The second Level 1 trigger requires a Level 2 Assessment.

Seasonal Systems

A seasonal system is a noncommunity public water system that is not operated year-round and starts up and shuts down at the beginning and end of each operating season. Examples of seasonal systems include campgrounds, ski areas, resorts, and some schools.

Monitoring

Seasonal systems transitioned to the RTCR on their existing total coliform schedule. All seasonal systems serving over 1,000 people or serving surface water including ground water under the direct influence of surface water will remain on monthly total coliform monitoring.

A seasonal system on quarterly total coliform monitoring will be placed on monthly total coliform monitoring the month after any of the following occur:

  • A Level 2 Assessment is triggered.
  • Failure to conduct an assessment or to take corrective actions in the time frame specified.
  • Failure to conduct start-up procedures before serving water to the public if not exempted.

A seasonal system that uses only ground water and serves 1,000 or fewer people may qualify for quarterly total coliform monitoring if the system meets all of the following:

  • An approved sample siting plan designates the most vulnerable period to bacterial contamination (highest use, wettest weather, etc.) and the owner or operator has collected samples during this period,
  • A sanitary survey was completed by DEQ with no significant deficiencies identified OR a Level 2 Assessment from a qualified party is completed and the system is free of sanitary defects,
  • A clean compliance history for the past 12 months, which means no MCL violations for total coliform (1989 rule) or E. coli, no monitoring violations for total coliform or E. coli, and no Level 1 or Level 2 Assessment triggers.
Start-up Procedures

The RTCR identified that seasonal systems are potentially more vulnerable to contamination when the system is dewatered during the off-season. Therefore, the rule requires that seasonal system owners complete start-up procedures before serving water to the public and certification that the procedures were completed must be turned in to DEQ or the Health District within 30 days following the start-up date.

Start-up Exemption

A seasonal system owner or operator may request to be exempted from performing start-up procedures if the entire distribution system remains pressurized and meets the following conditions:

  • Has no MCL violations for total coliform (1989 rule) or E. coli, no monitoring violations for total coliform or E. coli, and no Level 1 or Level 2 Assessment triggers within the past five years,
  • Has no uncorrected significant deficiencies from the most recent sanitary survey, and
  • Samples are submitted to a certified laboratory within 30 days before serving water to the public and the results are absent for total coliforms.

An exemption from performing start-up procedures will remain in effect unless any of the above conditions change.

Frequently Asked Questions

This section contains questions that are anticipated or asked by public water system owners or operators. Questions will be added to this section through time.

Monitoring

I only have one tap, how do I take my three repeat samples? DEQ may allow systems with a single tap to have the owner operator take either repeat samples over a 3-day period or take a larger volume (300 mL) of water in one or more sample containers. Please coordinate with DEQ or the Health District and your certified laboratory.

My system uses part surface water and part ground water and serves fewer than 100 people; can we take quarterly instead of monthly samples under the RTCR? The short answer is no. This part of the rule remains the same as the 1989 rule. Because your system uses surface water in any part, your system is classified as a surface water system (Subpart H system). Subpart H systems cannot reduce monitoring to less frequently than monthly monitoring regardless of size.

My system has a quarterly monitoring schedule; do we have to go to monthly with the RTCR on April 1, 2016? No, all systems will transition April 1 with the RTCR on their existing total coliform schedule whether it is monthly or quarterly. After April 1, 2016, if there are any triggers such as outlined for your system type above, your system will be placed on monthly monitoring.

Assessments

My system has an E. coli MCL violation; can I perform the Level 2 Assessment? DEQ or the Health District will conduct the Level 2 Assessment for systems experiencing E. coli MCL violations and work with you to identify the potential issues.

Can I conduct assessments if I don’t have a license? Level 1 Assessments can be performed by the owner or operator of the system or someone familiar with the system. An operator license is not required for a Level 1 Assessment but it is for a Level 2 Assessment. Level 2 Assessments will be conducted by DEQ or the Health District for E. coli MCL violations. Level 2 Assessments triggered for non-E. coli events can be performed by Idaho licensed drinking water treatment or distribution operators that are licensed at the level of the system or greater or an Idaho licensed professional engineer with experience in drinking water systems.

Public Notification

Do we still do provide public notification if my system has two total coliform positive samples in one month? If the samples were all negative for E. coli, no, you do not need to provide Tier 2 public notification. You will, however, have to conduct a Level 1 Assessment. The RTCR removed the maximum contaminant level for total coliforms and replaced the “monthly MCL” and Tier 2 notification with a requirement to perform a Level 1 Assessment as soon as practical and submit the assessment to DEQ within 30 days of the triggered event. (Note that if your system experiences two triggers for Level 1 Assessments in a rolling 12 month period, the second will be a Level 2 Assessment.)


Staff Contacts

Decision Support Lead
Monica Van Bussum
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0111
monica.vanbussum@deq.idaho.gov

DEQ Documents

Additional Resources

Environmental Protection Agency RTCR webpage

Environmental Protection Agency RTCR Key Provisions