Dichloromethane in Well Water: The Public 0.005 mg/L Line

By SubcontractorHub Editorial Team·Published October 2026

A solvent panel can list several names that share the digits 0.005. The row next to dichloromethane is not the row next to benzene, and it is not the row next to carbon tetrachloride. 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.

The Public 0.005 mg/L Line for Dichloromethane 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, dichloromethane shows an MCLG of zero and an MCL of 0.005. The potential health effects cell says liver problems and an increased risk of cancer. The source cell says discharge from drug and chemical factories.

Footnote 2 says units are in milligrams per liter unless otherwise noted, and that milligrams per liter are equivalent to parts per million. 0.005 mg/L is therefore 0.005 ppm on that note. Moving the same digits to micrograms per liter uses the 1,000-to-1 scale on milligrams and micrograms. 0.005 mg/L is 5 µg/L on that scale. Write both labels if the lab used the smaller unit, so a later reader does not think 5 is a new limit.

An MCLG of zero is a goal, not a statement that every jug at zero has been tested. An MCL is the enforceable public number. On this row the two cells do not match. The definitions of those two words are on MCL and MCLG. A zero goal is not a fine you can copy onto a private well.

One CAS Number, One MCL

Section 141.61, as printed on the Cornell eCFR page fetched the same day, lists dichloromethane as item (19), CAS 75-09-2, at 0.005 mg/L. The national table uses the name Dichloromethane. Older summaries put methylene chloride in parentheses beside that name. Those headings are one contaminant. Do not quote two limits because a lab sheet used the other common name.

Paragraph (a) says those volatile-organic levels apply to community and non-transient, non-community water systems. A private well is not named in that sentence. A dealer who copies the 0.005 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.

Dichloromethane in Well Water Is Not Benzene

Benzene prints an MCL of 0.005 mg/L on the same national table, with a source cell that names factories, gas storage tanks, and landfills. That is a different chemical. The benzene row has its own page, benzene in well water. Carbon tetrachloride also prints 0.005 mg/L, on carbon tetrachloride in well water. Tetrachloroethylene prints 0.005 mg/L as well, on tetrachloroethylene in well water. Three neighbors can share a digit and still be three rows.

Styrene is 0.1 mg/L, on styrene in well water. Do not paste a rubber-factory sentence onto dichloromethane because both names appear on a solvent panel. If the lab wrote dichloromethane, write dichloromethane. If the lab wrote methylene chloride, write that name and the same CAS if the sheet has one.

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 from landing in the scope.

What the BAT Marks Do Not Promise

Table 2 marks packed tower aeration for dichloromethane, CAS 75-09-2. Granular activated carbon is empty on that row, and oxidation is empty. Those marks identify a technology the rule names for compliance with the MCL. They do not say what percent a cartridge in a basement will remove, and they do not say an empty GAC cell is a ban on carbon you can explain as a product feature.

A city plant and a point-of-entry tank are not the same machine. If you sell aeration, say you sell aeration. Do not say the X in the PTA column is a guarantee on this well. No removal percentage was fetched for this row, so none is printed here. Styrene, on the same technology table, marks both GAC and PTA. Copying styrene's marks onto this row would invent a column the dichloromethane line left blank.

What Should the Dichloromethane in Well Water Note Say?

Five lines keep the next visit from borrowing a neighbor. 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, plus CAS 75-09-2 if the sheet has a CAS column.
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 0.005.
3. The public pair you compared it with: MCLG zero and MCL 0.005 mg/L, named as the national table.
4. Whether the sample is a private well or a public system. Paragraph (a) names community and non-transient, non-community systems.
5. What you did not claim: no removal percent, no installed price, and no statement that 0.005 mg/L is benzene's row.

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 0.005 mg/L line into a softener quote because the water “has a solvent” 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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