Heptachlor in Well Water: The Public 0.0004 mg/L Line

By SubcontractorHub Editorial Team·Published October 2026

A pesticide panel can list a parent chemical and a breakdown product on one page. The digit next to heptachlor is not the digit next to heptachlor epoxide, and it is not the digit next to chlordane, which shares the banned-termiticide source sentence. 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 0.0004 Line Is Not the Epoxide's 0.0002

EPA's national primary table, fetched the day this page was written, lists heptachlor with an MCLG of zero and an MCL of 0.0004 mg/L. The potential-effects cell says liver damage and an increased risk of cancer. The source cell says residue of a banned termiticide. Footnote 2 says units are milligrams per liter unless otherwise noted, and that milligrams per liter are equivalent to parts per million. This row did not opt out of that unit.

Heptachlor epoxide, on that same table, prints a goal of zero and an MCL of 0.0002 mg/L. Its health cell uses the same liver-damage sentence. Its source cell says breakdown of heptachlor. Sharing the health words is not sharing the digit, and sharing the parent name is not sharing the breakdown row. Quoting a bare 0.0004 without the name lets the next reader pick the epoxide, or pick chlordane.

Chlordane, on that same table, also says residue of a banned termiticide, and its MCL is 0.002 mg/L with a goal of zero. That row has its own page, chlordane in well water. Endrin prints 0.002 mg/L on both cells, with liver problems and a banned-insecticide source. The opening sentence of the national page says these standards apply to public water systems. It does not name a single-home well.

What the Heptachlor in Well Water Note Holds

The goal cell is zero. The page defines an MCLG as the level of a contaminant in drinking water below which there is no known or expected risk to health. It says MCLGs allow for a margin of safety and are non-enforceable public health goals. Zero on this row is that kind of goal. It is not a lab result of zero, and it is not a statement that the well has no heptachlor.

The MCL cell is 0.0004 mg/L. The page defines an MCL as the highest level of a contaminant that is allowed in drinking water. It says MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration, and that MCLs are enforceable standards. That definition is the public rule's definition. It is not a price for a filter, and it is not a percent removed.

The health cell is liver damage and an increased risk of cancer, described as a potential effect of long-term exposure above the MCL. That sentence is the public table's cell. It is not a finding about a person in the house. If a customer asks what the number means for a person, the honest line is that this page is not medical advice.

The source cell is residue of a banned termiticide. Keep that sentence on heptachlor. Do not shorten it to "banned chemical" and let the next reader pick endrin, which is an insecticide, or the epoxide, whose source cell is a breakdown product. The difference between a goal and an enforceable level is MCL and MCLG.

No Removal Percent Is Printed Here

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 epoxide's 0.0002, or chlordane's 0.002, from landing on a termiticide row that said 0.0004.

Best available technology, when a page names a mark, is explained in what is best available technology. No mark was fetched for heptachlor on this date, so none is printed. A carbon sentence copied from a neighbor is not this row.

What Should the Heptachlor in Well Water Note Say?

Five lines keep the public pair from being rewritten as a private-well fine or as the breakdown product.

1. The contaminant name as the lab printed it, and not heptachlor epoxide and not chlordane.
2. The result and the unit. If the unit is not milligrams per liter, do not drop the unit and call the result 0.0004.
3. The public pair you compared it with: MCLG zero and MCL 0.0004 mg/L, named as the national heptachlor row.
4. Whether the sample is a private well or a public system. The national page names public water systems. It does not name a single house.
5. What you did not claim: no removal percent, no installed price, no CAS, and no statement that 0.0004 mg/L is the epoxide's 0.0002 or chlordane's 0.002.

Where the Row Sits on the Job

Heptachlor in well water 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 0.0004 line into a carbon quote because the panel listed several banned names skips the name and skips the fact that the epoxide is a shorter digit on a related source sentence.

Both the goal and the MCL have to stay on the note. Zero is not the same kind of number as 0.0004. Dropping the goal because it is zero is how a later reader treats 0.0004 as if it were the only public figure, or as if a non-detect and the goal were the same sentence.

A banned-termiticide sentence is easy to reuse. Chlordane's source cell uses those words, and its MCL is 0.002. Endrin's source cell is a banned insecticide, and its digits are 0.002 on both cells. If the lab names heptachlor, keep the 0.0004 attached. Do not average it with 0.0002 because both names start with the same word.

How a dealer reads a full panel, including which tests were actually run, is the well water testing guide. A neighboring herbicide row at 0.1 mg/L is endothall in well water. 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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