Yuma County, AZ
These figures come from wells tested in Yuma County, AZ, not from any one well.
- Iron is common in wells in Yuma County, AZ (46 of 147 tested wells were over that level), so it's worth testing for.
- Manganese is common in wells in Yuma County, AZ (80 of 148 tested wells were over that level), so it's worth testing for.
- Sulfate is common in wells in Yuma County, AZ (568 of 774 tested wells were over that level), so it's worth testing for.
- Wells in Yuma County, AZ are typically very hard (829 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)
- manganese (common in wells here)
- sulfate (common in wells here)
- 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 | 31% |
| Wells over the level / wells judged | 46 of 147 |
| Median | 0.1 mg/L |
| Years sampled | 1951–2026 |
| Wells | 147 |
| Test results | 527 |
| Wells left out | 30 |
| Sources | USGS (203), AZDEQ_GW (145), 21ARIZGW (58) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 54% |
| Wells over the level / wells judged | 80 of 148 |
| Median | 0.175 mg/L |
| Years sampled | 1969–2026 |
| Wells | 148 |
| Test results | 511 |
| Wells left out | 24 |
| Sources | USGS (191), AZDEQ_GW (146), 21ARIZGW (58) |
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 88% |
| Median | 556 mg/L as CaCO₃ |
| Years sampled | 1929–2026 |
| Wells | 829 |
| Test results | 2,484 |
| Wells left out | 28 |
| Sources | USGS (628), AZDEQ_GW (145), 21ARIZGW (56) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 73% |
| Wells over the level / wells judged | 568 of 774 |
| Median | 450 mg/L |
| Years sampled | 1929–2026 |
| Wells | 774 |
| Test results | 2,389 |
| Wells left out | 22 |
| Sources | USGS (627), AZDEQ_GW (147) |