What Is the Revised Total Coliform Rule?

By SubcontractorHub Editorial Team·Published October 2026

Dealers who read a city notice still see the words total coliform and assume the old five percent monthly cap is the current federal MCL. EPA's own rule page says the biggest change is that there is no acute or monthly MCL violation for total coliform positive samples only. SubcontractorHub is software for the customer record. This page is the rule. It is not a treatment design, and it is not a finding that a jug of water is safe.

What a coliform hit means on a private-well panel stays on coliform bacteria in well water. Who counts as a public water system stays on what is a public water system. The ground-water rule, which uses a total-coliform-positive sample as a trigger for source monitoring, stays on what is the Ground Water Rule.

What the Revised Total Coliform Rule Requires

EPA's rule page, fetched the day this page was written, says EPA published the rule in the Federal Register on February 13, 2013, as 78 FR 10269, and minor corrections on February 26, 2014, as 79 FR 10665. It is the revision to the 1989 Total Coliform Rule, and it is intended to improve public health protection. All public water systems must comply starting April 1, 2016, or an earlier state effective date, except aircraft public water systems subject to the Aircraft Drinking Water Rule at 40 CFR 141 Subpart X.

The same page says total coliforms are a group of related bacteria that are, with few exceptions, not harmful to humans. EPA considers them a useful indicator of other pathogens for drinking water. They are used to determine the adequacy of water treatment and the integrity of the distribution system. That is an indicator sentence. It is not a diagnosis of a person, and it is not a cartridge size.

The key provisions named on the page are an MCLG and an MCL for E. coli, a total coliform treatment technique, monitoring under a sample siting plan, a transition that lets systems keep their existing Total Coliform Rule monitoring frequency, start-up duties for seasonal systems, assessments and corrective action, public notification for violations, and specific consumer-confidence-report language when a community system must conduct an assessment or incurs an E. coli MCL violation.

How the Revised Total Coliform Rule Differs From 1989

The key-provisions table on that page says the E. coli MCLG is set at zero. It says the E. coli MCL is based on the occurrence of a condition that includes routine and repeat samples. It does not print a milligrams-per-liter number for that condition. This page does not invent one. For total coliforms, systems must conduct a Level 1 or Level 2 assessment when they exceed a specified frequency of total coliform occurrences. The fetched paragraph says "a specified frequency." It does not print the count in that sentence, so this page does not supply a count and call it the rule.

An MCL violation, or a failure to take repeat samples after a routine total-coliform-positive sample, triggers a Level 1 or Level 2 assessment. Any sanitary defect identified during an assessment must be corrected. The page calls those the treatment technique requirements. It does not print a day count for the correction in the section fetched here, so none is added.

Under violations, the page says the biggest change is no acute or monthly MCL violation for total coliform positive samples only. That sentence is the split. The 1989 section on the same page still describes a monthly MCL: systems must not find coliforms in more than five percent of the samples they take each month. If a sample is total-coliform-positive, that older section says the system collects repeat samples within 24 hours at five or fewer sites next to the routine positive, and it takes at least five routine samples the next month if any sample is total-coliform-positive. Those clocks and counts belong to the 1989 section. They are not copied here as repeats under this revision.

What the Note Holds

The national primary table, fetched the same day, still prints footnote 4 under the total coliform row: no more than 5.0 percent of samples total-coliform-positive in a month, and for systems that collect fewer than 40 routine samples a month, no more than one total-coliform-positive sample. That footnote also describes an acute MCL when two consecutive samples are total-coliform-positive and one is also positive for E. coli or fecal coliforms. The rule page's biggest-change sentence says there is no acute or monthly MCL violation for total coliform positive samples only. A dealer who copies footnote 4 onto a 2026 notice should label it as the table's older line, not as this revision's treatment technique.

Monitoring the Page Actually Lists

The monitoring block says a system develops and follows a sample siting plan that designates the collection schedule, including where routine and repeat samples are taken. Routine samples are collected on a regular basis, and the page names monthly, quarterly, or annually. Samples are tested for total coliforms by a state-certified laboratory. Every routine or repeat sample that is total-coliform-positive is analyzed for E. coli.

Repeat samples are at least three for each total-coliform-positive routine sample. Systems on quarterly or annual routine sampling collect at least three additional routine samples in the month after a total-coliform-positive routine or repeat sample. Seasonal systems, described as non-community systems not operated year-round, must monitor and certify that they completed a state-approved start-up procedure.

Public notification is required for violations, using the required health-effects language inside the required timeframes. The page says the type of notice depends on the severity of the violation. It does not print those timeframes in the section fetched here, so this page does not invent a 24-hour or 30-day public notice clock and attribute it to the revision. Community systems use specific language in the consumer confidence report when they must conduct an assessment or when they incur an E. coli MCL violation. How to read that annual report is how to read a consumer confidence report.

What Should a Revised Total Coliform Rule Note Say?

Five lines keep a city notice from being filed as a private-well failure, and keep the 1989 five percent line from being filed as the current MCL.

1. Whether the paper is a public-system notice. The rule names public water systems. It does not name a single house.
2. Whether the hit is total coliform, E. coli, or both, as the notice prints it.
3. The E. coli goal the rule page prints: an MCLG of zero. Do not add a milligram cell the page did not print.
4. If the notice is about total coliforms only, say the rule page calls that a treatment technique, with a Level 1 or Level 2 assessment, not a monthly MCL for total coliform positives alone.
5. What you did not claim: no assessment deadline in days, no removal percent, no installed price, and no statement that footnote 4's 5.0 percent is this revision's monthly MCL.

Where the Rule Sits on the Job

A dealer who sells treatment to a house is not the primacy agency. The rule page is written for public water systems and for the states that carry it. A coliform result on a private well can still matter, and it still belongs on the customer record with the date and the lab. It does not become this rule because the words total coliform appear on both papers.

The Ground Water Rule uses a total-coliform-positive distribution sample as a reason for some ground-water systems to sample the source. That is a different rule, with its own page. Do not merge the assessment duty here with the 4-log virus sentence on the ground-water page. They were fetched as separate documents.

The customer file that holds the notice, the address, and the sample date is water treatment contractor software. A boil-water notice, when a system issues one, is what a boil water advisory is. This article does not size a UV unit and does not tell a household the water is safe to drink.

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