What Is a Treatment Technique in Drinking Water?

By SubcontractorHub Editorial Team·Published October 2026

What is a treatment technique is the question a dealer asks when a lab row says TT instead of a concentration. The national primary rules are legally enforceable primary standards and treatment techniques that apply to public water systems. SubcontractorHub is software for the customer record. This page is the definition. It is not a filter design, and it is not the action-level page.

The Note That Defines a Treatment Technique

The national primary drinking water regulations print the definition in the notes under the tables. A treatment technique is a required process intended to reduce the level of a contaminant in drinking water. An MCL, in the same notes, is the highest level of a contaminant that is allowed in drinking water. An MCLG is the level below which there is no known or expected risk to health, and MCLGs are non-enforceable public health goals. Those three sentences are not interchangeable. How the two concentration words differ is on MCL and MCLG.

Primary standards and treatment techniques protect public health by limiting the levels of contaminants in drinking water. The opening sentence of the page limits that duty to public water systems. A private well is not named there. The difference between a city system and a private well is what is a public water system. A dealer who copies a TT mark onto a kitchen-tap jug still has to say the jug is not the public-system rule.

Asking what is a treatment technique is how a later reader avoids treating the letters TT as an MCL. The Cornell text of 40 CFR 141.2 was fetched the same day. It did not contain a clean sentence that defines this term, so this page does not invent one from that section. The definition used here is the sentence in the national primary notes.

Which Rows Print a Treatment Technique

On the microorganism block, six rows print TT and point at footnote 3. Cryptosporidium and Giardia lamblia each show a goal of zero, a health cell of gastrointestinal illness such as diarrhea, vomiting, and cramps, and a source cell of human and animal fecal waste. Enteric viruses show a goal of zero, the same style of gastrointestinal illness, and fecal waste. Legionella shows a goal of zero, Legionnaire's Disease, a type of pneumonia, and a source cell that says it is found naturally in water and multiplies in heating systems.

Heterotrophic plate count shows n/a in the goal cell. The health cell says HPC has no health effects and is an analytic method used to measure the variety of bacteria that are common in water. The lower the concentration of bacteria in drinking water, the better maintained the water system is. HPC measures a range of bacteria that are naturally present in the environment. Turbidity also shows n/a. The health cell says turbidity is a measure of the cloudiness of water, used to indicate water quality and filtration effectiveness, and that higher turbidity levels are often associated with higher levels of disease-causing microorganisms. The source cell says soil runoff. The turbidity page is turbidity in well water. This page is the TT mark, not that contaminant article.

What the Note Holds, and What It Does Not

The table above is the note from the fetched national page. It is not a quote for a private well, and it is not a removal design you can hand a homeowner as a promise. A customer who wants a price still needs a test, a model, and a scope. Those live on the job.

What Footnote 3 Actually Requires

Footnote 3 says EPA's surface water treatment rules require systems using surface water, or ground water under the direct influence of surface water, to disinfect their water and filter their water, or meet criteria for avoiding filtration, so that the listed contaminants are controlled at the listed levels. Unfiltered systems are required to include Cryptosporidium in their existing watershed control provisions. Giardia lamblia is listed at 99.9 percent removal or inactivation. Viruses are listed at 99.99 percent removal or inactivation.

Legionella has no limit in that note. EPA believes that if Giardia and viruses are removed or inactivated according to the treatment techniques in the Surface Water Treatment Rule, Legionella will also be controlled. That sentence is a belief the agency printed about the surface-water rule. It is not a second number, and it is not a statement about a private well.

For systems that use conventional or direct filtration, turbidity can at no time go higher than 1 nephelometric turbidity unit, and samples for turbidity must be less than or equal to 0.3 NTU in at least 95 percent of the samples in any month. Systems that use filtration other than conventional or direct filtration must follow state limits, which must include turbidity at no time exceeding 5 NTU. Heterotrophic plate count is no more than 500 bacterial colonies per milliliter.

Those figures belong to the public surface-water rules in the footnote. They are not a cartridge rating, and they are not a promise that a basement filter hits 99.9 percent. Write the footnote number next to any percent you repeat, so a later reader can see which sentence you used.

Footnote 8 Is a Certification, Not a Percent Removed

Acrylamide and epichlorohydrin sit in the organic block, not in the microorganism block. Both show a goal of zero and TT with footnote 8. Acrylamide's health cell says nervous system or blood problems, and an increased risk of cancer. The source cell says it is added to water during sewage and wastewater treatment. Epichlorohydrin's health cell says increased cancer risk, and over a long period of time, stomach problems. The source cell says discharge from industrial chemical factories, and an impurity of some water treatment chemicals.

Footnote 8 says each water system must certify, in writing, to the state, using third-party or manufacturer's certification, that when acrylamide and epichlorohydrin are used to treat water, the combination or product of dose and monomer level does not exceed the specified levels. Acrylamide is 0.05 percent dosed at 1 mg/L, or equivalent. Epichlorohydrin is 0.01 percent dosed at 20 mg/L, or equivalent. Those percentages are about dose and monomer level. They are not a removal percentage for a contaminant already in a private well, and they are not an installed price.

Lead and Copper Use a Different Footnote

Footnote 7 says lead and copper are regulated by a treatment technique that requires systems to control the corrosiveness of their water. If more than 10 percent of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead it is 0.015 mg/L. Beginning on the LCRI compliance date of November 1, 2027, systems must comply with the revised lead action level of 0.010 mg/L.

That paragraph is why the lead row and the copper row can show TT without showing a single MCL. It is not footnote 3, and it is not footnote 8. The page that walks the action-level step is what is a drinking water action level. The lead row itself is lead in well water. Do not paste the 10 percent tap-sample rule onto Cryptosporidium, and do not paste a 99.9 percent Giardia figure onto a lead sample.

What Should the Treatment Technique Note Say?

Five lines keep the next visit from treating every TT as the same rule. Name the contaminant, name the footnote, and say whether the sample is a public system. If a line does not apply, mark it skipped. A blank line looks the same as a step you forgot, and a skipped line is still a line someone can read later.

1. The contaminant name as the table printed it, not the letters TT by themselves.
2. The footnote number. Footnote 3, footnote 7, and footnote 8 are different sentences.
3. The control figure you actually read, such as 99.9 percent for Giardia lamblia or 0.3 NTU in 95 percent of samples, with the filtration type attached.
4. Whether the sample is a private well or a public system. The opening sentence names public water systems.
5. What you did not claim: no installed price, and no statement that a basement cartridge meets a surface-water percent.

Where the Row Sits on the Job

The lab sheet belongs with the customer, the address, and the date of the sample. A price for equipment is a later page, after someone has read which footnote the row used. Mixing a turbidity NTU into an acrylamide certification, or mixing an action level into a virus percent, skips the footnote.

How a dealer reads a full panel, including which tests were actually run, is the well water testing guide. The software that holds the customer file is water treatment contractor software. This article does not size a filter and does not tell a household the water is safe to drink.

Frequently Asked Questions