Florence Water Company

PFAS monitoring results for a public water system in Arizona

AZ0411017UCMR 5EPA monitoring data
<MRLHighest PFOA result, ppt
<MRLHighest PFOS result, ppt
0.73Highest Hazard Index
270Results
PWSID
AZ0411017
State
Arizona
System type
community water system (CWS)
Population served
14,593
City
Florence
Counties
Pinal County
Primary source water
groundwater
UCMR 5 sampling
2023-09-05 to 2026-06-02 · 5 entry point(s) · water types: GW
Service-area boundary
authoritative

Hazard Index below its limit highest single result
Hazard Index below its limit worst entry-point average

These are monitoring results collected under EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) at entry points, where treated water enters the distribution system; they are not tap-water samples. They are not compliance determinations: compliance with EPA's 2024 PFAS limits is judged on running annual averages of compliance monitoring, required from 2029, so a single UCMR 5 result at or above a limit is not a violation. “< MRL” means the compound was not quantified at EPA's minimum reporting level; it does not mean zero.

Compared with EPA's 2024 values

Highest single resultWorst entry-point average*Limit
PFOA (ppt)<MRL04
PFOS (ppt)<MRL04
Hazard Index0.730.3661.0†

“<MRL” = every result for the compound was below its reporting limit. * Mean of all samples at each entry point with non-detects = 0 (EPA compliance convention; the Hazard Index also uses non-detects = 0); a screening comparison, not a formal running annual average. † Rescission proposed May 2026. PFOA/PFOS MCL 4 ppt (2024 NPDWR, in effect). PFHxS, PFNA, HFPO-DA (10 ppt each) and the Hazard Index (1.0) are 2024 NPDWR values; EPA proposed rescinding them on 18 May 2026 (comment period closed 20 Jul 2026).

No Arizona PFAS drinking-water standard in effect or proposed as of 2026-10-17: No Arizona-specific PFAS drinking-water standard; ADEQ adopts federal drinking-water rules by reference (A.A.C. Title 18, Ch. 4).

Sampling history

Sampled 2023-09-05 to 2026-06-02 · 5 entry point(s) · water types: GW · 9 sampling visits. PFAS in ppt (ng/L).

DateEntry pointEventPFOAPFOSHIOther detections
2023-09-05Well 1 TP (GW)SE1<4<40.73PFBA 9, lithium 172 µg/L
2023-09-05Well 2B (GW)SE1<4<40.305lithium 114 µg/L
2023-09-05Well 3B TP (GW)SE1<4<40lithium 105 µg/L
2023-09-05Well 4 TP (GW)SE1<4<40lithium 291 µg/L
2024-03-05Well 1 TP (GW)SE2<4<40.003lithium 162 µg/L
2024-03-05Well 2B (GW)SE2<4<40lithium 112 µg/L
2024-03-05Well 3B TP (GW)SE2<4<40lithium 146 µg/L
2024-03-05Well 4 TP (GW)SE2<4<40lithium 320 µg/L
2026-06-02Well 5 TP (GW)SE2<4<40lithium 130 µg/L

“<4” = not detected at the reporting limit shown; “n/a” = not analyzed in that sample. Highlighted = at or above the 4 ppt MCL. HI computed per sample with non-detects as 0. Other detections lists every other quantified compound (lithium in µg/L).

All results by entry point

270 results. Each column is one sampling visit (date and UCMR 5 sample event). A number is a measured concentration; “< 4” = below the minimum reporting level shown; “–” = not analyzed in that visit. PFAS in ppt (ng/L); lithium in µg/L.

Well 1 TP facility 20001 · sample point POE003 · groundwater

CompoundMRL2023-09-05
SE1
2024-03-05
SE2
PFBA5 ppt9< 5
PFBS3 ppt605.1
PFHxS3 ppt7< 3
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
6:2 FTS5 ppt< 5< 5
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxA3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFOA4 ppt< 4< 4
PFOS4 ppt< 4< 4
PFPeA3 ppt< 3< 3
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L172162

Well 2B facility 20005 · sample point POE005 · groundwater

CompoundMRL2023-09-05
SE1
2024-03-05
SE2
PFBS3 ppt10< 3
PFHxS3 ppt3< 3
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
6:2 FTS5 ppt< 5< 5
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFBA5 ppt< 5< 5
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxA3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFOA4 ppt< 4< 4
PFOS4 ppt< 4< 4
PFPeA3 ppt< 3< 3
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L114112

Well 3B TP facility 20002 · sample point POE004 · groundwater

CompoundMRL2023-09-05
SE1
2024-03-05
SE2
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
6:2 FTS5 ppt< 5< 5
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFBA5 ppt< 5< 5
PFBS3 ppt< 3< 3
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxA3 ppt< 3< 3
PFHxS3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFOA4 ppt< 4< 4
PFOS4 ppt< 4< 4
PFPeA3 ppt< 3< 3
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L105146

Well 4 TP facility 20003 · sample point POE002 · groundwater

CompoundMRL2023-09-05
SE1
2024-03-05
SE2
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
6:2 FTS5 ppt< 5< 5
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFBA5 ppt< 5< 5
PFBS3 ppt< 3< 3
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxA3 ppt< 3< 3
PFHxS3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFOA4 ppt< 4< 4
PFOS4 ppt< 4< 4
PFPeA3 ppt< 3< 3
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L291320

Well 5 TP facility 20004 · sample point POE001 · groundwater

CompoundMRL2026-06-02
SE2
11Cl-PF3OUdS5 ppt< 5
4:2 FTS3 ppt< 3
6:2 FTS5 ppt< 5
8:2 FTS5 ppt< 5
9Cl-PF3ONS2 ppt< 2
ADONA3 ppt< 3
HFPO-DA5 ppt< 5
NEtFOSAA5 ppt< 5
NFDHA20 ppt< 20
NMeFOSAA6 ppt< 6
PFBA5 ppt< 5
PFBS3 ppt< 3
PFDA3 ppt< 3
PFDoA3 ppt< 3
PFEESA3 ppt< 3
PFHpA3 ppt< 3
PFHpS3 ppt< 3
PFHxA3 ppt< 3
PFHxS3 ppt< 3
PFMBA3 ppt< 3
PFMPA4 ppt< 4
PFNA4 ppt< 4
PFOA4 ppt< 4
PFOS4 ppt< 4
PFPeA3 ppt< 3
PFPeS4 ppt< 4
PFTA8 ppt< 8
PFTrDA7 ppt< 7
PFUnA2 ppt< 2
lithium9 µg/L130

Statistics by compound

CompoundResultsDetectedHighest (date)Mean boundsKM medianP75P90P95
lithium9100%320
2024-03-05
172.44–172.44146172320320
PFBS933%60
2023-09-05
8.34–10.34<MRL5.16060
PFHxS922%7
2023-09-05
1.11–3.44<MRL<MRL77
PFBA911%9
2023-09-05
1–5.44<MRL<MRL99

Never detected (26): 11Cl-PF3OUdS, 4:2 FTS, 6:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFDA, PFDoA, PFEESA, PFHpA, PFHpS, PFHxA, PFMBA, PFMPA, PFNA, PFOA, PFOS, PFPeA, PFPeS, PFTA, PFTrDA, PFUnA.

Left-censored Kaplan–Meier statistics (Helsel 2005; Helsel & Lee 2006, NADA for R). Units: ppt; lithium µg/L. Each compound has one reporting limit, so the Kaplan–Meier mean equals the upper mean bound (non-detects at the MRL); the lower bound sets non-detects to 0. “<MRL” = the percentile falls below the reporting limit and cannot be estimated. These describe this system's UCMR 5 samples, not population estimates.

Sources

  • EPA UCMR 5 occurrence data text files (UCMR5_All.txt; samples 2023-01-03 to 2026-06-02; data summary dated Jul 2026)
  • EPA SDWIS via ECHO SDWA downloads, quarter 2026Q3
  • EPA Public Water System Service Areas v3 (Mar 2026)
  • US Census Bureau cartographic boundary counties 1:500k, 2024
  • EPA/USGS NHDPlus V2 (medium resolution) flowlines, Strahler order 2+

Data build e94d59d510ac · 2026-10-18T04:09Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.