Hays County, TX · PWSID TX1050001
City of San Marcos lead service lines
1,515 lead or galvanized lines to replace
City of San Marcos reported 0 lead and 1,515 galvanized-requiring-replacement service lines out of 17,681 in its inventory. That's about 1 in 12 lines. Another 3,146 (18%) are still listed as unknown material.
Ranks #14 of 534 Texas systems with confirmed lead lines, and #286 nationally.
8.6% of City of San Marcos's service lines are lead or galvanized requiring replacement. That's higher than the Texas average (1.2%) and higher than the national average (3.1%).
- Lead 0%
- Galvanized (replace) 8.6%
- Unknown 18%
- Non-lead 74%
Total service lines reported: 17,681. Reported all required service line types. Population served: 72,970; 42,746 connections.
Lead test results
City of San Marcos's most recent 90th-percentile lead result (Jan 2022–Dec 2024) was 1.6 ppb, below both the 15 ppb action level and the 10 ppb level that takes effect in 2027. This means 90% of homes sampled were at or below that level; individual homes, especially those with lead lines, can be higher.
Lead and Copper Rule 90th-percentile results reported to EPA, in parts per billion. Dashed lines: 15 ppb action level and the 10 ppb level from November 1, 2027.
Progress since 2025 Q1
Reported lead and galvanized-requiring-replacement lines went from 1,515 in 2025 Q1 to 1,515 in 2026 Q3: no change. Lines of unknown material went from 3,146 to 3,146, no change.
Quarterly counts reported to EPA. A drop usually means lines were replaced or confirmed non-lead; a rise usually means more lines were identified. Replacement progress rankings.
Lead rule violations
EPA's data lists 1 Lead and Copper Rule violation since 2015 for City of San Marcos. Health-based violations are treatment failures, such as corrosion control or public education; the rest are missed monitoring or reporting.
| Began | Violation | Status |
|---|---|---|
| Dec 2015 | Lead consumer notice not delivered or reported | Returned to compliance |
Source: EPA SDWIS violation records for the Lead and Copper Rule.
Where the water comes from
City of San Marcos's main water source is surface water (rivers, lakes or reservoirs). It buys treated water from Alliance Regional Water Authority 1b. The seller treats the water, including corrosion control that keeps lead from dissolving out of pipes, while City of San Marcos is responsible for its own service line inventory and replacement program. It sells water to 3 other water systems: City of Kyle, Texas State University - San Marcos, Gbra Ih-35 Transmission Main.
Source: EPA SDWIS water system and facility records.
Check your own address
These counts cover the whole system. To see whether your line is lead, use the utility's address-level inventory. Utilities had to prepare one by October 16, 2024 and make it publicly accessible; systems serving more than 50,000 people must post it online.
No map yet? Do the 2-minute scratch and magnet test on the pipe where water enters your home.
Protect your drinking water now
If your line is lead, galvanized or unknown, filter water for drinking, cooking and baby formula. Use a filter certified to NSF/ANSI 53 for lead. Run cold water for a few minutes after it sits for hours, and never use hot tap water for cooking.
How to pick a lead-certified filter · How to test your water for lead
Getting the line replaced
EPA's Lead and Copper Rule Improvements require most systems to replace lead and galvanized-requiring-replacement lines by December 31, 2037. Ask City of San Marcos whether it replaces the private side for free or with a cost share before you hire anyone. If you want it done sooner, or your utility doesn't cover your side, a licensed plumber can quote it. What replacement costs.
County pages: Lead pipes in Hays County
Cities served
ZIP codes served
ZIP codes whose center falls inside City of San Marcos's mapped service area (EPA service area boundaries). Neighboring utilities may serve parts of the same ZIP.
78666
Other water systems nearby
| System | Lead + galv. | Unknown |
|---|---|---|
| City of Kyle | 99 | 0 |
| Texas State University - San Marcos | 16 | 0 |
| City of Buda | 185 | 0 |
| Dripping Springs WSC | 0 | 143 |
| Woodcreek Utility 2 | 0 | 38 |
| Oak Meadows | 0 | 324 |
| Cardinal Valley Water | 0 | 36 |
| Wimberley Oaks WSC | 0 | 16 |
Check another water system
Questions
Does City of San Marcos have lead pipes?
Yes. City of San Marcos reported 0 lead service lines and 1,515 galvanized lines that must be replaced, out of 17,681 total. 3,146 more are of unknown material.
How do I check if my home's service line is lead?
Look up your address on City of San Marcos's official service line inventory, which utilities must make publicly available. You can also scratch the pipe where it enters your home: lead is soft, dull gray, scratches to shiny silver and does not attract a magnet.
When will City of San Marcos replace lead service lines?
Under EPA's Lead and Copper Rule Improvements, most systems must replace lead and galvanized-requiring-replacement lines by December 31, 2037, starting from November 1, 2027. The rule is being challenged in court, so dates could change. Many utilities run free or cost-share programs now.
Has City of San Marcos had lead violations?
EPA's data shows 1 Lead and Copper Rule violation since 2015 for City of San Marcos.
Which water filters remove lead?
Use a filter certified to NSF/ANSI Standard 53 for lead reduction, or NSF/ANSI 58 for reverse osmosis. Check the certification on NSF's listings, not just the box.
Embed or cite this data
Local news sites, blogs and community groups can embed this card. It updates when EPA releases new data.
Citation: Lead Pipe Map, "City of San Marcos lead service lines," https://leadpipemap.com/tx/city-of-san-marcos/. Source: EPA SDWIS service line inventory, 2026 Q3. Download the full dataset on the data page.