Table 1 –

UCMR3 PFAS Concentrations by Drinking Water Utility System Size^a and Source Water Type^b

Small Systems – Surface Water (n = 1,199)									Small Systems – Groundwater (n = 2,075)
PFAS	# Detects	Det. Freq.c (%)	Concentration (ng/L)						PFAS	# Detects	Det. Freq. (%)	Concentration (ng/L)
			MRLd	Mean	SDe	Median	P90f	Max.g				MRL	Mean	SD	Median	P90	Max.
PFBS	0	0	90	--	--	--	--	--	PFBS	0	0	90	--	--	--	--	--
PFHxS	0	0	30	--	--	--	--	--	PFHxS	4	0.19	30	409	348	404	718	730
PFHpA	0	0	10	--	--	--	--	--	PFHpA	4	0.19	10	41	35	33	76	87
PFOA	0	0	20	--	--	--	--	--	PFOA	4	0.19	20	100	85	81	183	206
PFOS	2	0.17	40	54	6	54	58	59	PFOS	4	0.19	40	158	127	142	279	300
PFNA	0	0	20	--	--	--	--	--	PFNA	1	0.05	20	26	--	26	26	26
Large Systems – Surface Water (n = 13,279)									Large Systems – Groundwater (n = 20,419)
PFAS	# Detects	Det. Freq. (%)	Concentration (ng/L)						PFAS	# Detects	Det. Freq. (%)	Concentration (ng/L)
			MRL	Mean	SD	Median	P90	Max.				MRL	Mean	SD	Median	P90	Max.
PFBS	12	0.09	90	212	94	185	357	370	PFBS	7	0.03	90	136	49	110	196	220
PFHxS	28	0.21	30	69	35	62	79	190	PFHxS	175	0.86	30	144	174	79	330	1,600
PFHpA	92	0.69	10	19	11	15	39	60	PFHpA	140	0.69	10	28	43	20	53	410
PFOA	101	0.76	20	31	13	29	41	100	PFOA	274	1.34	20	45	46	30	74	349
PFOS	66	0.50	40	77	56	57	140	400	PFOS	220	1.08	40	200	603	64	383	7,000
PFNA	1	0.01	20	54	--	54	54	54	PFNA	17	0.08	20	35	11	32	52	56

^aSystems ≤10,000 population served = “Small” and >10,000 = “Large”;

^b“Surface water” also includes groundwater under the influence of surface water and mixed sources;

^cDetection frequency, only detections ≥MRL reported;

^dMinimum reporting level;

^eStandard deviation;

^f90^th Percentile;

^gMaximum; “--” = not applicable