North Mohave Valley

PFAS monitoring results for a public water system in Arizona

AZ0408068UCMR 5EPA monitoring data
<MRLHighest PFOA result, ppt
5.5Highest PFOS result, ppt
0.342Highest Hazard Index
120Results
PWSID
AZ0408068
State
Arizona
System type
community water system (CWS)
Population served
5,190
City
Bullhead City
Counties
Mohave County
Primary source water
groundwater
UCMR 5 sampling
2025-02-03 to 2025-08-06 · 2 entry point(s) · water types: GW
Service-area boundary
authoritative

PFOS 1–3 × its limit highest single result
PFOS 1–3 × 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)5.55.24
Hazard Index0.3420.3271.0†

“<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 2025-02-03 to 2025-08-06 · 2 entry point(s) · water types: GW · 4 sampling visits. PFAS in ppt (ng/L).

DateEntry pointEventPFOAPFOSHIOther detections
2025-02-03Well Treatment TP001 (GW)SE1<4<40lithium 95 µg/L
2025-02-05Well Treatment/Storage Tanks 1/2 (GW)SE1<44.90.312PFPeA 3.4, lithium 42 µg/L
2025-08-05Well Treatment TP001 (GW)SE2<4<40lithium 100 µg/L
2025-08-06Well Treatment/Storage Tanks 1/2 (GW)SE2<45.50.342PFHxA 3, PFPeA 3.2, lithium 44 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

120 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 Treatment TP001 facility TP001 · sample point EPDS001 · groundwater

CompoundMRL2025-02-03
SE1
2025-08-05
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/L95100

Well Treatment/Storage Tanks 1/2 facility TP003 · sample point EPDS003 · groundwater

CompoundMRL2025-02-05
SE1
2025-08-06
SE2
PFBS3 ppt3.63.6
PFHxA3 ppt< 33
PFHxS3 ppt3.13.4
PFOS4 ppt4.95.5
PFPeA3 ppt3.43.2
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
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFOA4 ppt< 4< 4
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L4244

Statistics by compound

CompoundResultsDetectedHighest (date)Mean boundsKM medianP75P90P95
lithium4100%100
2025-08-05
70.25–70.254495100100
PFBS450%3.6
2025-02-05
1.8–3.3<MRL3.63.63.6
PFHxS450%3.4
2025-08-06
1.62–3.12<MRL3.13.43.4
PFOS450%5.5
2025-08-06
2.6–4.6<MRL4.95.55.5
PFPeA450%3.4
2025-02-05
1.65–3.15<MRL3.23.43.4
PFHxA425%3
2025-08-06
0.75–3<MRL<MRL33

Never detected (24): 11Cl-PF3OUdS, 4:2 FTS, 6:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFBA, PFDA, PFDoA, PFEESA, PFHpA, PFHpS, PFMBA, PFMPA, PFNA, PFOA, 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.