Skip to content

EPA ID GA0670003 · checked 16 Oct 2026

Cobb County tap water: what EPA testing found

Cobb County Water System (EPA record: COBB COUNTY) serves 695,000 people in GA from surface water purchased.

What the data shows

PFAS and lithium (EPA UCMR 5)

120 results from 1 sampling points, 7 Aug 2023 to 6 May 2024. Averages count results below EPA’s reporting level as zero, as the PFAS rule does. Every number links to EPA’s UCMR 5 Data Finder (search PWSID GA0670003). Limits: EPA PFAS rule.

ContaminantDetected inHighest resultAverageEPA limit
PFOA0 of 4not detected0 ng/L4 ng/L
PFOS0 of 4not detected0 ng/L4 ng/L
PFHxS0 of 4not detected0 ng/L10 ng/L*
PFNA0 of 4not detected0 ng/L10 ng/L*
HFPO-DA0 of 4not detected0 ng/L10 ng/L*
PFBS4 of 44.2 ng/L3.58 ng/Lnone
PFBA1 of 46.5 ng/L1.63 ng/Lnone
PFHxA1 of 43.2 ng/L0.8 ng/Lnone
Lithium0 of 4not detected0 µg/Lnone (screening level 10 µg/L)

* PFHxS, PFNA and HFPO-DA limits (and the PFAS hazard index) are in the rule, but EPA proposed on 20 May 2026 to rescind them; not final as of 16 Oct 2026. UCMR 5 results are screening data, not compliance results: compliance uses quarterly running averages from 2029. Source file: EPA UCMR 5 occurrence data (dated 15 Oct 2026).

Health-based violations since 2016

None in EPA’s SDWIS data.

Source: EPA SDWIS via Envirofacts and the ECHO report for GA0670003, retrieved 16 Oct 2026.

Hardness

2.1 grains per gallon (highest plant or source figure of 2, 2025; varies by area), from the utility’s water report checked 16 Oct 2026. Size a softener for this water.

Plant, source or areaServesGrains per gallon
James E. Quarles Water Treatment Plant (Chattahoochee River)–1.85
Hugh A. Wyckoff Water Treatment Plant (Lake Allatoona)–2.05

From the same report. Which plant or source serves an address depends on where it is; the utility’s report explains its areas.

Places and ZIP codes served

Marietta, Acworth, Austell, Kennesaw, Smyrna, Atlanta, Hiram, Mableton, Powder Springs, Roswell, Woodstock.

30008 30060 30062 30064 30066 30067 30068 30075 30080 30082 30101 30102 30106 30126 30127 30141 30144 30152 30168 30188 30339

ZIP codes the system reported to EPA for UCMR 5; place names from GeoNames (CC BY 4.0). A ZIP code can be split between systems.