Does a detection mean the water is unsafe or out of compliance?

No. UCMR 5 is monitoring data and does not indicate compliance or noncompliance with any drinking-water standard. It reports the highest single detected result at the entry point, which is information you can act on by testing your own tap and choosing a certified filter.

PFAS detected in Puerto Rico water systems

Q: Which Puerto Rico water systems had PFAS detected in EPA UCMR 5?

EPA UCMR 5 detected PFOA or PFOS at or above 6 parts per trillion in 9 large Puerto Rico public water systems (each serving more than 10,000 people). Select a system to see the specific PFAS and highest levels detected.

EPA UCMR 5 monitoring (2023–2025) detected PFOA or PFOS at or above 6 parts per trillion in these 9 large Puerto Rico public water systems, each serving more than 10,000 people. Select a system to see exactly what was detected and the certified filters that reduce it.

Puerto Rico systems, highest detections first

Water system	PFOA (ppt)	PFOS (ppt)	vs. 4 ppt reference
Aibonito La Plata	—	46.7	11.7×
Ponce Urbano	5.1	25.6	6.4×
Patillas Urbano	—	14.3	3.6×
Metropolitano	10.9	7.8	2.7×
Santa Isabel Urbano	—	10.3	2.6×
Cidra Urbano	—	9.8	2.5×
Caguas Norte	—	7.4	1.9×
Manati East	—	6.7	1.7×
Morovis Urbano	—	6.7	1.7×

Highest single EPA UCMR 5 detections (2023–2025), in parts per trillion. The last column is the multiple of the 4 ppt federal reference level for PFOA/PFOS — shown as context only, not a compliance or health determination. — means the compound was not detected at or above 6 ppt.

Not sure what's in your own water? Test it first, then run the selector for a recommendation matched to your home, or read what PFAS is and how it's removed.