US Tap Water May Hold Twice the PFAS Reported
By Sustainability Awakening • Dr. Ahmad Mahmood
New study
Reports catch only 44%
44%
Share of average PFAS captured when low results count as zero.
Source: Cell Reports Sustainability
The blind spot
98% fall below the limit
Of 1.8 million EPA test records, 98% were under lab reporting limits and logged as zero.
Source: TCU-led study
Six regulated PFAS
The average doubles
Counted as zero2.6 ppt
Modelled estimate5.2 ppt
Source: 9,991 community water systems
Forever chemicals
What PFAS are
Synthetic chemicals from nonstick pans, stain-proof fabric and firefighting foam that barely break down.
Why it matters
Health goal: zero
Some PFAS are linked to cancer, liver damage and developmental harm. EPA’s health goal for PFOA and PFOS is zero.
The rules
Limits in flux
PFOA, PFOS limit4 ppt
Proposed deadline2031
Other 4 limitsProposed repeal
Source: EPA, May 2026
Read the label
‘Not detected’ isn’t zero
It means below a 2–20 ppt reporting limit, not PFAS-free.
Source: EPA UCMR 5
What you can do
Pick certified filters
Pitcher or tapNSF/ANSI 53
Reverse osmosisNSF/ANSI 58
Check the PFAS claim for your exact model.
Know your water
Check your utility first
Your annual water quality report and EPA’s UCMR 5 data show what was found nearby.