What Is a Drinking Water Health Advisory?

By SubcontractorHub Editorial Team·Published October 2026

A homeowner can hand you a PDF and call every number on it a limit. Some numbers are enforceable standards. Some are goals. Some are advisories written for a spill. The job is to say which document you are holding before anyone prices a filter. SubcontractorHub keeps the customer file. This page is the difference between those documents.

What a Drinking Water Health Advisory Is Allowed to Be

The EPA drinking water health advisories page, last updated March 30, 2026, says the Safe Drinking Water Act authorizes health advisories for contaminants that are not subject to a national primary drinking water regulation. The citation on the page is 42 U.S.C. §300g-1(b)(1)(F). The documents give technical information on chemical and microbial contaminants that can cause human health effects and are known or anticipated to occur in drinking water.

A health advisory value identifies the concentration at which adverse health effects, or aesthetic effects, are not anticipated over a specific exposure duration. The examples the page gives are 1 day, 10 days, and a lifetime. A number with no duration is not the whole advisory. Write the duration next to the value if you are looking at a real table, and do not invent a duration the PDF did not print.

The same page says advisories primarily serve as information to drinking water systems and to officials responsible for protecting public health when emergency spills or other contamination situations occur. They help states, Tribes, and local governments inform the public and decide whether local action is needed. That audience is not a sentence that fines a private well. A private well is explained on what is a public water system.

A Drinking Water Health Advisory Is Not an MCL

The health-advisory page also defines the two words dealers already mix up. An MCLG is the level below which there is no known or expected risk to health. It allows a margin of safety and is a non-enforceable public health goal. An MCL is the highest level of a contaminant allowed in drinking water. MCLs are set as close to the goals as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.

A health advisory is a third thing. The page says health advisories are not to be construed as legally enforceable federal standards, and that they are subject to change as new information becomes available. Quoting an advisory as if the state can fine the utility for it, when the page says it is not enforceable, is the mistake this article is here to stop. The longer comparison of the goal and the enforceable number is MCL and MCLG.

If the contaminant already has a national primary regulation, you are not in advisory territory for that rule. Xylenes, ethylbenzene, toluene, and the other rows with an MCL live on their own pages. Do not paste an advisory concentration over an MCL because both are “EPA numbers.”

What the Note Holds, and What It Does Not

Interim Advisories Can Be Replaced

EPA says it can develop interim or provisional health advisory levels for an urgent or rapidly developing situation. Those levels are also based on health-based hazard concentrations above which action should be taken to reduce exposure to unregulated contaminants. They can be updated or removed. The example on the page is specific: provisional health advisories for PFOA and PFOS in 2009, and interim updated health advisories for PFOA and PFOS in 2022.

This article does not repeat a concentration from those advisories. The page that already covers the regulated PFAS discussion on this site is PFAS in well water. If a customer brings a PFAS advisory, read the year on their PDF before you compare it with a different year. The health-advisory page also says the March 2018 Drinking Water Standards and Health Advisories tables do not include the 2022 PFAS health advisories. A 2018 PDF is not the 2022 update.

About Two Hundred Rows, Each With a Duration

The page says the standards and health-advisories tables contain levels for approximately 200 contaminants, based on non-cancer health effects for one-day, ten-day, and lifetime exposures, plus the reference dose behind a lifetime value or, if applicable, a cancer risk value. The same tables also list contaminants that are regulated, with their MCLGs and MCLs. A regulated row inside that PDF is still an MCL when you are talking about enforcement. The advisory columns are the other columns.

Approximately 200 is EPA's word on that page. It is not a count of chemicals in a particular well, and it is not a count of pages you should print for one customer. Open the row they asked about. Leave the other 199 alone unless the lab actually reported them.

Not a Boil Water Advisory

People say “advisory” for more than one notice. A boil water advisory, a do-not-drink notice, and a do-not-use notice are the three CDC types on what is a boil water advisory. Boiling is the instruction for one of those notices. A chemical health advisory is not that instruction. The health-advisory page does not tell you to boil the water. If you tell a household to boil a chemical contaminant because the word advisory appeared, you have mixed two documents.

The health-advisory page also lists microbial documents by title and date, including cyanotoxin materials from June 2015, a Cryptosporidium advisory from March 2001, Giardia from November 1999, Legionella from March 2001, and Mycobacteria from August 1999. Those titles are not concentrations. This page does not copy a microgram value out of them. If you need the number, open the document the customer has, and write the year.

What Should a Drinking Water Health Advisory Note Say?

Five lines keep the PDF from becoming a fake MCL. If a line does not apply, mark it skipped.

1. The contaminant name, and the year on the document.
2. The duration the value uses: one day, ten days, a lifetime, or the duration actually printed.
3. Whether the page you used calls the number an advisory or an MCL. Do not upgrade an advisory.
4. Who the sample belongs to: a public system, or a private well that is not that system.
5. What you did not claim: no concentration you did not read, no boil instruction, and no installed price.

Where the Notice Sits on the Job

The PDF, the date, and the customer address belong in one file. A later visit should be able to see that you compared an advisory, not an MCL, and which year's table you opened. EPA says it anticipates developing health advisories for additional PFAS as toxicity assessments are published. A note that says “the latest advisory” without a date will be wrong the next time the page changes.

How a dealer reads a lab panel is the well water testing guide. The software that holds the customer file is water treatment contractor software. This article does not say a filter will meet an advisory, and it does not say the water is safe to drink.

Frequently Asked Questions