Atrazine in Well Water: The Public 0.003 mg/L Line

By SubcontractorHub Editorial Team·Published October 2026

A herbicide panel can list several names that share a runoff sentence, and the digit next to this name is not the digit next to alachlor, simazine, or glyphosate. Dealers who sell treatment still have to say which public line they are reading. SubcontractorHub is software for the customer record. This page is the row. It is not a treatment design, and it is not medical advice.

The Public 0.003 mg/L Line for Atrazine in Well Water

The national primary drinking water regulations are legally enforceable primary standards and treatment techniques that apply to public water systems. In the organic block, atrazine shows an MCLG of 0.003 and an MCL of 0.003. The potential health effects cell says cardiovascular system or reproductive problems. The source cell says runoff from herbicide used on row crops.

Footnote 2 says units are in milligrams per liter unless otherwise noted, and that milligrams per liter are equivalent to parts per million. 0.003 mg/L is therefore 0.003 ppm on that note. That conversion is not a second standard. Moving the same digits to micrograms per liter uses the 1,000-to-1 scale on milligrams and micrograms. 0.003 mg/L is 3 µg/L on that scale. Write both labels if the lab used the smaller unit, so a later reader does not think 3 is a new limit.

An MCLG is a non-enforceable public health goal. An MCL is the enforceable public number. On this row the two cells print the same 0.003 figure. That match is the point of reading both cells before anyone quotes a neighbor. The definitions of those two words are on MCL and MCLG. A goal is not a fine. A nearby herbicide with a different digit is still a different name.

The 0.003 mg/L Figure in the Organic Table

Section 141.61, as printed on the Cornell eCFR page fetched the same day, lists maximum contaminant levels for synthetic organic contaminants. Atrazine is item (c)(1)(v), CAS 1912-24-9, at 0.003 mg/L. Paragraph (c) says those MCLs apply to community water systems and non-transient, non-community water systems. A private well is not named in that sentence. A dealer who copies the 0.003 mg/L line onto a kitchen-tap jug still has to say the jug is not the public-system rule. The difference between a city system and a private well is what is a public water system.

The same Cornell page marks atrazine under granular activated carbon on the best-available-technology table. Packed tower aeration is empty. Oxidation is empty. Those marks identify a technology the rule names. They do not say what percent a cartridge will remove. No removal percentage was fetched for this row, so none is printed here. Ethylbenzene, a volatile neighbor with its own 0.7 mg/L line, is a different page, ethylbenzene in well water.

The 0.003 mg/L Line Is Not the Neighbor Herbicide

Alachlor, on the same national table, prints a goal of zero and an MCL of 0.002. The health cell says eye, liver, kidney, or spleen problems, anemia, and an increased risk of cancer. The source cell uses the same sentence this row uses: runoff from herbicide used on row crops. The shared sentence is why a hurried note collapses the two names. The goal does not match. The MCL does not match. The health sentence does not match.

Simazine prints 0.004 and 0.004. The health cell says problems with blood. The source cell says herbicide runoff, which is a shorter sentence than the row-crop line. Glyphosate prints 0.7 and 0.7. The health cell says kidney problems and reproductive difficulties. The source cell says runoff from herbicide use. Cornell's MCL table also prints glyphosate at 0.7 mg/L. Its BAT table spells the name Gylphosate and marks oxidation rather than granular activated carbon. This page does not treat that spelling as a second chemical, and it does not copy 0.7 onto atrazine.

Nitrate, measured as nitrogen, is 10 and 10 on the inorganic block. The health cell is about infants below six months. The source cell names runoff from fertilizer use, leaking from septic tanks and sewage, and erosion of natural deposits. A farm sentence is not this herbicide row. Nitrate has its own page, nitrates in well water. Adding atrazine to nitrate, or to alachlor, does not create a limit the rule printed.

What the Note Holds, and What It Does Not

The table above is the note. It is not a quote, and it is not a removal design. A customer who wants a price still needs a test, a model, and a scope. Those live on the job. This page only stops the wrong digit, or the right digit on the wrong herbicide, from landing in the scope. A health advisory is a different kind of number, explained on what is a drinking water health advisory. This page did not fetch an advisory value, so none is printed.

What the GAC Mark Does Not Promise

Granular activated carbon is the column Cornell marked for this contaminant. The other two columns on that organic BAT table, packed tower aeration and oxidation, are blank for atrazine. A blank column is not a hidden second technology. A marked column is not a percent. A city plant and a point-of-entry tank are not the same machine.

If you sell carbon, say you sell carbon. Do not say the mark is a guarantee on this well. Do not borrow glyphosate's oxidation mark, or ethylbenzene's 0.7, because a panel listed more than one organic name. The health cell you are allowed to repeat is cardiovascular system or reproductive problems. That is the public table's potential-effects cell. It is not a finding about the household.

What Should the Atrazine in Well Water Note Say?

Five lines keep the next visit from borrowing a neighbor herbicide. Name the chemical the lab printed, show both the goal and the MCL, and say whether the jug is a private well. If a line does not apply, mark it skipped. A blank line looks the same as a step you forgot.

1. The chemical name as the lab printed it, not alachlor, not simazine, and not glyphosate.
2. The result and the unit. If the unit is µg/L, show the mg/L equivalent on the 1,000 scale before anyone compares it with 0.003.
3. The public pair you compared it with: MCLG 0.003 mg/L and MCL 0.003 mg/L, named as the national row, and CAS 1912-24-9 if you are reading the Cornell item.
4. Whether the sample is a private well or a public system. Paragraph (c) names community and non-transient, non-community systems for the synthetic-organic MCLs.
5. What you did not claim: no removal percent, no installed price, and no statement that 0.003 mg/L is alachlor's 0.002 or glyphosate's 0.7.

The Unit Change Is Not a New Limit

0.003 mg/L and 3 µg/L are the same public figure written two ways, using the 1,000 scale already on this site. 0.003 ppm is the same figure again, because footnote 2 says milligrams per liter are equivalent to parts per million. A lab that prints 3 next to micrograms has not discovered a stricter line. A lab that prints 0.003 next to milligrams has not discovered a looser one. Write the unit beside the digit every time the number moves from the sheet to the proposal.

CAS 1912-24-9 is the identifier Cornell prints on item (c)(1)(v). If the lab header uses that number and not the common name, the row is still this one. Do not attach the number to alachlor, which is a different CAS on the same table, or to simazine. The GAC mark stays a mark. It does not become a percent because the CAS matched.

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 this row and the rows next to it. Mixing the 0.003 mg/L line into a carbon quote because the panel listed several herbicides skips the chemical name.

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.

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