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

By SubcontractorHub Editorial Team·Published October 2026

Dealers meet tetrachloroethylene in well water on a lab sheet that also lists other solvents, often next to a name that sounds the same. The annual city packet is a consumer confidence report. This page is only the tetrachloroethylene row. The national primary rules apply to public water systems. They are not a private-well statute. How to order the jug is the well water testing guide. Which systems count as public is what a public water system is.

Tetrachloroethylene in Well Water on the Primary Table

The national primary drinking water regulations are legally enforceable primary standards and treatment techniques that apply to public water systems. In the organic block, tetrachloroethylene's MCLG cell is zero. The MCL is 0.005. The potential health effects listed are liver problems and an increased risk of cancer. The source cell says discharge from factories and dry cleaners.

The table notes put those figures in milligrams per liter unless otherwise noted. The notes say milligrams per liter are equivalent to parts per million. 0.005 mg/L is therefore 0.005 ppm on that note. It is not a different standard. 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 is a goal. An MCL is the enforceable public number. Zero in the goal cell is not a second MCL sitting under 0.005. The definitions of those two words are on MCL and MCLG.

The 0.005 Figure in the 2025 CFR

Section 141.61 of the 2025 Code of Federal Regulations prints maximum contaminant levels for volatile organic contaminants. Tetrachloroethylene, CAS 127-18-4, is 0.005 mg/L. Trichloroethylene, CAS 79-01-6, is also 0.005 mg/L and sits earlier on that table. The shared digits are not a shared row. The metal-degreasing row is trichloroethylene in well water. Benzene is a third 0.005 mg/L row, with gas tanks and landfills in its source cell, on benzene in well water.

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 line onto a kitchen-tap jug still has to say the jug is not the public-system rule. The difference between a city report and a private well is private well water regulations.

What Is the Tetrachloroethylene Row Next To?

Some lab sheets shorten tetrachloroethylene to PCE and trichloroethylene to TCE. The letters are not interchangeable. PCE on this page is CAS 127-18-4. TCE is CAS 79-01-6. Vinyl chloride remains a different number, 0.002 mg/L, on vinyl chloride in drinking water. If the sheet does not name the chemical, do not pick the dry-cleaner row because a cleaner used to operate nearby.

How to Read Tetrachloroethylene in Well Water on a Ticket

Five lines keep the public number from becoming a filter pitch. None of them is a removal percent.

1. The name on the lab row, and the CAS if the sheet has one. 127-18-4 is tetrachloroethylene.
2. The unit. If the sheet says µg/L, convert with the 1,000 scale before you compare it with 0.005 mg/L.
3. Whether the sample is a private well or a public system. The CFR sentence names community and non-transient non-community systems.
4. The source cell you are not using. Dry cleaners are this row. Metal degreasing is trichloroethylene. Gas tanks are benzene.
5. A blank where a removal percent would go. This page does not have one.

Other 0.005 Rows Are Not This Dry-Cleaner Line

The 2025 volatile-organic table prints 0.005 mg/L for more than this chemical. Carbon tetrachloride is CAS 56-23-5. 1,2-Dichloroethane is CAS 107-06-2. Benzene is CAS 71-43-2. Trichloroethylene is CAS 79-01-6. Tetrachloroethylene is CAS 127-18-4. Toluene, the next line after tetrachloroethylene on that table, is 1 mg/L, not 0.005.

A highlighter on every 0.005 will mix a dry-cleaner row with a metal-degreasing row and with benzene. Write 127-18-4 when the sheet has it. If the sheet says PCE and does not give a CAS, say that PCE on this page means tetrachloroethylene, and that you did not confirm the CAS. Do not borrow toluene's 1 mg/L, and do not borrow a health cell this page did not fetch for the other solvents.

What This Row Does Not Decide

The health-effects cell is EPA's description of long-term exposure above the MCL. It is not a diagnosis of the person who handed you the jug. Do not turn “liver problems” into advice about a customer's health. Send medical questions to a clinician.

The source cell is also not a verdict about this house. Discharge from factories and dry cleaners is what the table lists. It does not prove a former cleaner on the block caused this sample. A dealer who needs the system type, rather than the solvent row, should stay on the public-water-system page. A dealer who needs the whole primary list should use primary and secondary drinking water standards.

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