Coconino County, AZ
These figures come from wells tested in Coconino County, AZ, not from any one well.
- Iron is common in wells in Coconino County, AZ (12 of 100 tested wells were over that level), so it's worth testing for.
- Sulfate is common in wells in Coconino County, AZ (87 of 480 tested wells were over that level), so it's worth testing for.
- Manganese is not common in wells in Coconino County, AZ (6 of 88 tested wells were over). Only a test tells you about your own well.
- Wells in Coconino County, AZ are typically very hard (526 wells tested).
- Only a test of your own well tells you about your water.
What to test for
Start with the four this site covers:
- iron (common in wells here)
- sulfate (common in wells here)
- manganese
- hardness
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. Arizona's certified-lab list (from your state drinking-water program)
The numbers
County figures describe the wells sampled there, not any one well. Exact counts, sample years and sources are below.
Iron Recent
| Level it's compared with | 0.3 mg/L |
|---|---|
| Share of wells over the level | 12% |
| Wells over the level / wells judged | 12 of 100 |
| Median | 0.025 mg/L |
| Years sampled | 1951–2026 |
| Wells | 100 |
| Test results | 683 |
| Wells left out | 7 |
| Sources | USGS (268), HOPI_WQX (42), 21ARIZGW (30), AZDEQ_GW (17), 11NPSWRD_WQX (6), AZDEQ_SW (1) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 6.8% |
| Wells over the level / wells judged | 6 of 88 |
| Median | 0.01 mg/L |
| Years sampled | 1955–2026 |
| Wells | 88 |
| Test results | 512 |
| Wells left out | 8 |
| Sources | USGS (189), HOPI_WQX (42), 21ARIZGW (30), AZDEQ_GW (17), 11NPSWRD_WQX (6), AZDEQ_SW (1) |
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 53% |
| Median | 199.5 mg/L as CaCO₃ |
| Years sampled | 1933–2026 |
| Wells | 526 |
| Test results | 980 |
| Wells left out | 5 |
| Sources | USGS (426), HOPI_WQX (46), 21ARIZGW (31), AZDEQ_GW (17), 11NPSWRD_WQX (5), AZDEQ_SW (1) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 18% |
| Wells over the level / wells judged | 87 of 480 |
| Median | 42 mg/L |
| Years sampled | 1933–2025 |
| Wells | 480 |
| Test results | 864 |
| Wells left out | 7 |
| Sources | USGS (418), HOPI_WQX (44), AZDEQ_GW (17), AZDEQ_SW (1) |