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Counties → Texas

Williamson County, Texas

SDWIS compliance plate

Sheet TX491 · Williamson County 52 sys · 2,502 viol · #98/3254

VIOL-SEVERE · HEALTH-LOW · RANK-TOP · PHOTO-FINISH · PFAS-HIGH · SRC-SW · SYS-MID · BOOK-FULL

  • VIOL-SEVERE 98.1% flagged
  • HEALTH-LOW 9.3% health
  • RANK-TOP #98/3254
  • PHOTO-FINISH ±0.1 pp
  • PFAS-HIGH 82.4% detect
  • SRC-SW SW lead 62%
  • SYS-MID 52 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Grayson County ( -0.1 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Williamson County ranks #98 of 3,254 counties by people served, and #12 of 254 counties in Texas. See methodology · corpus placement.

Williamson County standing, mid-flagged corpus third

Flagged-system rate 98.1% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 9.3% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 82.4% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #98 of 3,254 · #12 of 254 in Texas.

Flagged-rate neighbourhood around Williamson County

Lowest/highest poles plus in-state counties nearest Williamson County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.

0% 20% 40% 60% 80% 100% Howard · lowest Val Verde · near Williamson · this county Bee · highest 66.7% 97% 97.3% 98% 98.1% 98.3% 100%

Source: EPA SDWIS (county aggregates) As of 2026-05-15

Water Systems

System Name Population Violations PFAS
City of Georgetown 191,639 15 Detected
City of Round Rock 130,662 16 Detected
City of Leander 98,330 29 Detected
City of Cedar Park 86,939 37 Detected
Jonah Water Sud 29,861 69 Detected
City of Hutto 29,580 25 Clean
City of Taylor 20,622 43 Detected
Brushy Creek MUD 18,314 45 Detected
Sonterra MUD 16,614 23 Detected
Jarrell Schwertner WSC 9,681 32 Detected
City of Liberty Hill 8,777 136 -
Williamson County Wsid 3 8,265 33 Detected
Block House MUD 6,618 5 Detected
Williamson Travis County MUD 1 5,793 28 Clean
Fern Bluff MUD 5,682 1 Detected
Williamson County MUD 11 4,248 1 Detected
Williamson County MUD 10 3,513 4 Detected
City of Jarrell 3,450 13 -
Paloma Lake MUD 1 3,111 6 -
City of Bartlett 2,950 241 Clean
Vista Oaks MUD 2,724 17 -
Paloma Lake MUD 2 2,265 1 -
City of Granger 1,914 63 -
Blessing Mobile Home Park 1,518 68 -
Durham Park WSC 1,251 83 -
City of Florence 1,136 98 -
City of Thrall 975 44 -
Tal Tex 939 9 -
San Gabriel River Ranches 891 218 -
Walsh Ranch MUD 714 4 -
Brushy Bend Park 645 15 -
South San Gabriel Ranches 510 21 -
Sunny Creek Mhc 510 266 -
High Gabriel WSC 492 309 -
Inner Space Cavern 310 33 -
San Gabriel River RV Camp Resort 300 16 -
Round Rock Ranch PUD Utility Company 285 12 -
Smilin V Ranch 256 4 -
Mesa Rosa Restaurant 250 76 -
Community Christian Church 180 43 -
Txdps Tactical Training Center 124 26 -
Round Rock Roller Rink 100 27 -
Liberty Greenline 46 47 -
200 County Road 314 37 103 -
County Cottage Lines 29 1 -
Premier Athletic Complex 25 28 -
Liberty Hill Tri-Air Park 25 37 -
Live Oak Water Delivery 25 20 -
Juniper RV Park 21 6 -
Brazos River Authority Granger Lake Regi 0 1 -

Compare beyond Texas

Mid-flagged peers for Williamson County

Cross-state counties nearest Williamson County on flagged-system share (98.1%) and cumulative violation count (2,502). In-state neighbours stay on the compliance plate above.

Similar flagged-system rate

Nearest cross-state counties by % of SDWIS systems with at least one violation on record.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers

Read our methodology · Check your water system - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.