01The verdict: is Dilley water safe? Dilley's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (70/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 4,505 residents using groundwater (wells). The concern13 unresolved violations on record EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching. See what was cited ↓ The good newsLead is well under the limit 90th-percentile lead is 0.5 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold. See the trend ↓ Keep watchinglithium is approaching its limit Measured at 41.4000 µg/L — 120% of the 0.004 µg/L limit. Within the rules, but with less headroom than you'd want. See the ledger ↓ Dilley's drinking water received a grade of C+ (70 out of 100), indicating fair water quality. The city's 1 water system serves approximately 4,505 residents using groundwater. Lead levels were measured at 0.5 ppb (90th percentile), well within EPA limits. UCMR 5 testing detected 1 PFAS compound in the water supply. The system has 22 violations on record, including 2 health-based violations. 13 remain unresolved. Dilley ranks #575 out of 1067 cities in Texas for water quality, placing it below average in the state. Dilley relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. PFAS compounds were detected in testing, though levels remain within current EPA limits. Residents seeking extra precaution may consider an activated carbon or reverse osmosis filter. The system has seen 10 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely. ViolationsHistorical violation record including health-based and monitoring violations. 23.7 / 45D Lead & CopperLead at 0.5 ppb (90th percentile). 20 / 20A Contaminants1 PFAS compound detected. 18.2 / 20A ComplianceMonitoring and reporting compliance with EPA regulations. 3 / 10F Source RiskWater source: Groundwater. 5 / 5A 02What's in Dilley's water Every contaminant flagged in Dilley, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has. 3 detections · sorted by % of legal limit Over the limit Elevated — watch Within limits 0 50% LEGAL LIMIT 150% lithium PFAS / Forever Chemical 41.4000 µg/L 120% of limit Lithium Inorganic 41.4 µg/L 69% of limit Lead (90th percentile) Inorganic / Heavy Metal · + details 0.5 ppb 3% of limit 32 contaminants tested under EPA SDWIS, LCR and UCMR programs · 3 detected All Tested Contaminants Contaminant Detected Level EPA Limit Unit Category Status Lead (90th percentile) 0.5 15 ppb Inorganic Safe 11Cl-PF3OUdS ND HI µg/L PFAS Not Detected 4:2 FTS ND HI µg/L PFAS Not Detected 6:2 FTS ND HI µg/L PFAS Not Detected 8:2 FTS ND HI µg/L PFAS Not Detected 9Cl-PF3ONS ND HI µg/L PFAS Not Detected ADONA ND HI µg/L PFAS Not Detected HFPO-DA ND 0.01 µg/L PFAS Not Detected lithium 41.400 HI µg/L PFAS Detected NEtFOSAA ND HI µg/L PFAS Not Detected NFDHA ND HI µg/L PFAS Not Detected NMeFOSAA ND HI µg/L PFAS Not Detected PFBA ND HI µg/L PFAS Not Detected PFBS ND HI µg/L PFAS Not Detected PFDA ND HI µg/L PFAS Not Detected PFDoA ND HI µg/L PFAS Not Detected PFEESA ND HI µg/L PFAS Not Detected PFHpA ND HI µg/L PFAS Not Detected PFHpS ND HI µg/L PFAS Not Detected PFHxA ND HI µg/L PFAS Not Detected PFHxS ND HI µg/L PFAS Not Detected PFMBA ND HI µg/L PFAS Not Detected PFMPA ND HI µg/L PFAS Not Detected PFNA ND HI µg/L PFAS Not Detected PFOA ND 0.004 µg/L PFAS Not Detected PFOS ND 0.004 µg/L PFAS Not Detected PFPeA ND HI µg/L PFAS Not Detected PFPeS ND HI µg/L PFAS Not Detected PFTA ND HI µg/L PFAS Not Detected PFTrDA ND HI µg/L PFAS Not Detected PFUnA ND HI µg/L PFAS Not Detected Data source: EPA SDWIS, UCMR 5, local utility CCR. 03Dilley's ten-year track record Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 22 violations on record, including 2 health-based violations. 13 remain unresolved. 2017 3 violations 2018 1 1 open 2019 clean 2020 clean 2021 1 violation 2022 clean 2023 1 1 open 2024 6 6 open 2025 2 2 open 2026 clean 4 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues. 2 health-based in 10 yrs 12 monitoring & paperwork 10 still unresolved UCMR 5 TestingPFAS1 PFAS "forever chemical" compound detectedDetected at levels within current EPA limits. PFAS persist indefinitely in the environment.July 2026UpdateWater quality data updatedLatest EPA compliance and testing data incorporated into Dilley's water quality assessment. Grade: C+ (70/100).July 2025Violation1 drinking water violation recordedContaminants: Consumer Confidence Rule.OpenMay 2025Violation1 drinking water violation recordedContaminants: Public Notice.OpenOctober 2024Violation3 drinking water violations recorded1 health-based. Contaminants: Public Notice, LEAD AND COPPER RULE REVISIONS.OpenSeptember 2005DisasterHURRICANE RITAFederal disaster declaration (FEMA DR-1606). Hurricane event — may have impacted local water infrastructure. Lead, 90th percentileppb · lower is better05101520EPA action level · 15 ppb1993 — 2.3 ppb1994 — 3.5 ppb1995 — 2.2 ppb1996 — 7.2 ppb1999 — 4.8 ppb2007 — 6.4 ppb2013 — 1.6 ppb2014 — 1.1 ppb2017 — 0 ppb2018 — 0.70 ppb2021 — 0.50 ppb2024 — 0.50 ppb2.30.5019931996201320182024▼ Down 1.8 ppb since 1993. Latest reading: 0.50 ppb (2024) — 3% of the action level. Sampled at higher-risk homes (90th percentile). 04Where Dilley's water comes from Dilley's drinking water is drawn from underground aquifers through wells. SourceGroundwater Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate. TreatmentLocal treatment Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal. Distribution1 system 1 water system (1 wholesaler), operated under local government ownership. Delivery4,505 people Residents served across Dilley's service area. Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by local government ownership and serves approximately 4,505 people through 1 water system. System namePWSIDPopulationSource CITY OF DILLEY TX0820001 4,505 Groundwater Water bodies near Dilley Frio Rv Nr Derby · river These water bodies shape the regional watershed and can indirectly affect groundwater quality. 05Pressure on Dilley's watershed Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about. Present — monitored2 facilities within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed. MULTI-CHEM GROUP DILLEY TX FACILITY 0 lb · 2.8 mi CHAMPIONX-DILLEY 0508 0 lb · 1.3 mi Occasional1 federal disaster declaration on record for Frio County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies. HURRICANE RITA Sep 2005 · DR-1606 D1 — moderate drought Frio County is in D1 (moderate drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs. Weeks at D2+ in the last 5 years19 wks Months in D2+ over the last 30 years27.6% 06How Dilley compares Scores for nearby Texas cities on one line, with the average marked. Dilley (this city)70 · C+ dashed line = Texas average (46/100)Dilley scores 70/100 — above the Texas average of 46/100. It outscores 8 of 10 nearby cities. Full Texas rankings →Frio water quality rankingsCompare all cities in the county — grades, violations, and contaminant data side by side.→ 07What to do at home Steps matched to what testing actually found in Dilley's water — not generic advice. Because of pfasFilter drinking & cooking water Activated carbon or reverse osmosis filter. 1 PFAS compound detected Compare tested filters → Know your reportRead your utility's annual report Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page. How to read a CCR → Stay informedWatch for Dilley alerts We refresh EPA data monthly and surface new violations, advisories, and boil-water notices for your county on this page. All water alerts → FAQ Is Dilley, TX tap water safe to drink? Dilley's water quality earned a grade of C+ (70/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #575 out of 1067 cities tested in Texas. What contaminants are in Dilley's water? Lead was measured at 0.5 ppb (90th percentile). 1 PFAS compound was detected. 22 violations are on record. How is Dilley's water quality grade calculated? The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details. Do I need a water filter in Dilley? PFAS compounds have been detected. A filter with activated carbon can help reduce exposure. Where does Dilley's water come from? Dilley's water is sourced from Groundwater. The city has 1 water system serving approximately 4,505 residents. What health violations has Dilley's water system had? Dilley has 2 health-based violations on record. The most recent violation was recorded in July 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 13 violations remain unresolved. Is Dilley's groundwater at risk of contamination? Dilley uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 22 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS. How does Dilley's water compare to other cities? Dilley ranks #575 out of 1067 cities in Texas (better than 46% of state cities) and #10671 out of 15382 cities nationally (31th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance. About Dilley, TX: Dilley is a town in Frio County, Texas, United States. The population was 3,274 at the 2020 census. It is located off Interstate 35, south of the county seat in Pearsall. Median household income $59,044 · median home value $116,159 · median age 33.2 · 73.1% homeowners · 10.1% college educated. Wikipedia → Service area: 1 ZIP code across Frio. Show ZIP codes 78017 Sources: EPA SDWIS & ECHO · UCMR 3–5 · Lead & Copper Rule samples · EPA TRI · U.S. Drought Monitor · FEMA declarations. Data last updated Jul 2026. Analysis by the WaterVerge Editorial Team · methodology.