Sequoyah County, OK

These figures come from wells tested in Sequoyah County, OK, not from any one well.

Too few wells have been tested in Sequoyah County, OK (7 each) to say how common iron, manganese or sulfate is.

What to test for

Start with the four this site covers:

Most well owners also test for these. We point to the source and don't interpret the results.

arsenic: occurs naturally in groundwater in many regions. USGS: arsenic and drinking water
nitrate: common near farmland and septic systems. EPA: private drinking water wells
total coliform bacteria: the standard yearly well check. EPA: private drinking water wells
lead and copper: from household plumbing, especially when pH is below 6.5. EPA: lead in drinking water
PFAS: several states run private-well sampling programs. EPA: PFAS
a certified lab: states certify labs and some run their own private-well programs. Oklahoma's certified-lab list (from your state drinking-water program)

County figures describe the wells sampled there, not any one well. Exact counts, sample years and sources are below.

Level it's compared with	0.3 mg/L
Share of wells over the level	43%
Wells over the level / wells judged	3 of 7
Median	0.1 mg/L
Years sampled	1981
Wells	7
Test results	7
Wells left out	0
Sources	USGS (7)

Fewer than 10 wells behind this figure; treat it as a hint, not a prior.

Level it's compared with	0.05 mg/L
Share of wells over the level	86%
Wells over the level / wells judged	6 of 7
Median	0.12 mg/L
Years sampled	1981
Wells	7
Test results	7
Wells left out	0
Sources	USGS (7)

Fewer than 10 wells behind this figure; treat it as a hint, not a prior.

Level it's compared with	250 mg/L
Share of wells over the level	0.0%
Wells over the level / wells judged	0 of 7
Median	28 mg/L
Years sampled	1981
Wells	7
Test results	7
Wells left out	0
Sources	USGS (7)

Fewer than 10 wells behind this figure; treat it as a hint, not a prior.