Full contaminant data, sample history, and sourcing for Waller County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
196 well testing events on record, covering
20 analytes.
Data spans 1930 to 2017.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. TX Avg
Iron
122
1942–2021
48%
32% of limit
↓ 79% below
Arsenic
74
1990–2021
45%
24% of limit
↓ 37% below
Manganese
80
1960–2021
58%
29% of limit
↓ 54% below
Chloride
42
1930–2014
100%
22% of limit
↓ 40% below
Fluoride
159
1942–2021
99%
7% of limit
↓ 71% below
HFPO-DA (GenX)
municipal
23
2023–2025
0%
—
—
Lead
73
1990–2021
5%
6% of limit
↓ 65% below
Nitrate
43
1944–2014
93%
3% of limit
↓ 86% below
Nitrite
2
2002–2014
0%
—
—
PFHxS
municipal
23
2023–2025
0%
—
—
PFNA
municipal
23
2023–2025
0%
—
—
PFOA
municipal
23
2023–2025
0%
—
—
PFOS
municipal
23
2023–2025
0%
—
—
Radon
2
2002–2014
100%
20% of limit
↓ 45% below
Sulfate
42
1930–2014
98%
3% of limit
↓ 90% below
Uranium
31
2002–2021
58%
4% of limit
↓ 74% below
Sodium
31
1930–2014
100%
—
↓ 59% below
pH
29
1944–2014
100%
—
~ typical
PFBS
municipal
23
2023–2025
0%
—
—
Hardness
40
1930–2014
100%
—
↓ 35% below
Distribution shows the share of samples in each concentration band relative to the EPA Maximum Contaminant Level (MCL): Low = below half the MCL, Moderate = between half and the MCL, High = above the MCL. Analytes without an MCL (e.g. sodium, pH) show — in the limit columns. State average is based on county median values across TX.
Compare your result with Waller County
Of the 74 arsenic tests on record for Waller County (1990–2021),
55% found none.
Of the 42 chloride tests on record for Waller County (1930–2014),
0% found none, and half were below 54 mg/L.
Of the 159 fluoride tests on record for Waller County (1942–2021),
1% found none, and half were below 280 µg/L.
Of the 122 iron tests on record for Waller County (1942–2021),
52% found none.
Of the 73 lead tests on record for Waller County (1990–2021),
95% found none.
Of the 80 manganese tests on record for Waller County (1960–2021),
42% found none, and half were below 2.16 µg/L.
Of the 43 nitrate tests on record for Waller County (1944–2014),
7% found none, and half were below 260 µg/L.
Of the 42 sulfate tests on record for Waller County (1930–2014),
2% found none, and half were below 6.85 mg/L.
Of the 31 uranium tests on record for Waller County (2002–2021),
42% found none, and half were below 51 ng/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Iron 122 samples
Arsenic 74 samples
Manganese 80 samples
Chloride 42 samples
Fluoride 159 samples
Lead 73 samples
Nitrate 43 samples
Sulfate 42 samples
Uranium 31 samples
Sodium 31 samples
pH 29 samples
Hardness 40 samples
Limited data (<15 samples) — interpret with caution
Nitrite 2 samples
Radon 2 samples
No private-well PFAS data for Waller County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Waller County.
PFAS testing for private wells requires a dedicated lab panel (~$300–$500). If you are near a military base, airport, or industrial site, consider testing proactively. Learn more about PFAS →
Public vs. Private Water in Waller County
74Active public water systems
61,713Residents on public water
13%Households on private wells
Public water systems in Waller County are regulated by the EPA and must test and report contaminant levels. Private well owners are responsible for their own testing — there is no routine monitoring of private wells by any government agency.
CDC Health Outcome Correlations
Where contaminants detected in Waller County have established associations with specific health outcomes, we cross-reference CDC PLACES county-level prevalence data. This is a contextual signal, not a causal claim.
This report aggregates data from the following public databases:
Water Quality Portal (WQP) — groundwater sample results for Waller County from EPA, USGS, and state agencies. Browse WQP data →
EPA Safe Drinking Water Information System (SDWIS) — public water system inventory used to estimate the share of residents on private wells. Browse SDWIS →
Census ACS 5-Year Estimates — well and cistern household counts (variable DP04_0074E) used to calculate the private-well percentage for Waller County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Waller County, which informs which contaminants are geologically likely. USGS Aquifer Atlas →
EPA UCMR 5 (2023–2025) — PFAS occurrence data from public water systems, used as a proxy indicator for aquifer PFAS exposure. Rows marked "municipal" in the table above come from this source. About UCMR 5 →
EPA Toxics Release Inventory (TRI) — industrial facility chemical releases near Waller County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Waller County, used in contamination risk scoring. Superfund site search →
CDC PLACES — county-level health outcome prevalence (kidney disease, cancer, heart disease) correlated with detected contaminants. About CDC PLACES →
Methodology
Raw records are downloaded from the Water Quality Portal and normalized to µg/L (ppb). Records are deduplicated by sample ID and date, and certified outliers are excluded. Analyte names are mapped to EPA canonical forms. Detection rates, distribution bands, and MCL comparisons are computed from the normalized dataset.
Distribution bands use the EPA Maximum Contaminant Level as the threshold: concentrations below 50% of the MCL are classed as Low, between 50% and 100% as Moderate, and above 100% as High. For analytes without an MCL (sodium, hardness, pH), distribution is not computed.
State comparison uses the median of county median values across all counties in TX with at least one sample for that analyte.