Tahlequah, OK Water Quality: Hardness, Iron and Wells

Tahlequah Public Works Authority supplies the city, and its water is all surface water. There is no groundwater in the city supply. That single fact explains most of what people taste: river and lake water carries organic matter, organic matter takes a lot of disinfectant to make safe, and disinfectant leaves byproducts behind.

The utility's own Consumer Confidence Report names both sources. The report on this page is the one published in 2026, covering calendar year 2025, and it is free to download from the utility. The utility reports serving 14,458 people. Cherokee County has about 47,942 residents, so most of the county is not on this system at all — those homes are on a rural water district or a private well.

The Environmental Working Group keeps a page for Tahlequah PWA. It uses the utility's own reported numbers, averaged over 2021 to 2023, and compares them against EWG's own health guidelines rather than the legal limits. Those guidelines are much stricter than the law. EWG is an advocacy group, not a regulator, and nothing in the table below is a violation of anything.

We include it because it is what you will find if you search, and because it is the clearest published statement of what different filters actually do for this water. EWG's own filter panel for Tahlequah PWA says a reverse osmosis system covers all twelve of the contaminants on its exceedance list, while an activated carbon filter covers ten of them.

You will also find third-party sites that give the utility a letter grade. Those grades are one group's interpretation of the same report. They are not findings by a regulator, and we are not going to repeat them as though they were.

The water under this county comes from the Boone and Roubidoux aquifers. The Boone is Mississippian limestone and it is karst: the USGS describes it as containing sinkholes, caves and enlarged fractures. Karst carries water fast and along paths nobody can see, which is why two wells a mile apart can test nothing alike and why a well here can change within days of heavy rain. Below the Boone, the Roubidoux is dolomite with limestone and sandstone in it.

Limestone and dolomite are where hardness comes from. They are also why iron, manganese and sulfide show up in some wells and not in the next one over. There is no single answer for well water in Cherokee County, and anyone who gives you one has not tested yours.

Oklahoma does not regulate private wells. Oklahoma DEQ puts it plainly: if you are not on a public water system, you alone are responsible for making sure your water is safe. Well drilling and pump installation are overseen by the Oklahoma Water Resources Board, which also keeps a searchable record of wells in the state.

One more thing that matters here: almost every house on a well is also on a septic system. OSU Extension's guidance is to keep at least 75 feet between a water well and a septic system, and 100 feet if the well sits downslope of the drain field, and to keep the well casing standing at least 12 inches above the ground. Statewide, 49 percent of Oklahoma houses built between 2002 and 2021 have a septic system, against about 20 percent nationally.

The EPA sets secondary standards for the substances that do not threaten health but do wreck laundry, fixtures and appliances. They are not enforced on public systems, and nothing enforces them on your well. They are still the most useful numbers on a water test, because they tell you where a problem becomes visible.

If your lab report shows iron above 0.3 mg/L or manganese above 0.05 mg/L, the staining you are seeing has a name and a treatment.

Everything on this page is published data from the sources listed below, gathered in one place because nobody else around here has done it. We did not measure any of it ourselves, and none of these numbers describe your house.

If you are on a private well, get a test from an Oklahoma DEQ certified laboratory. It is the only way to know what you have, and it costs less than the wrong equipment. If you are on Tahlequah city water, the utility's annual report is free and it is the real thing — read it rather than anybody's summary of it, including ours.

For a water main break, a boil order or a question about your meter, call Tahlequah PWA on 918-456-2564. That number is printed in their report. For the plumbing inside your house, and for treatment equipment, call or text us on (918) 822-7918. Oklahoma plumbing license OK203156.