Water Health Check Report

San Antonio, TX

San Antonio Water System (Saws) · Blended supply source · Edwards Aquifer karst groundwater (~60% of supply) blended with Guadalupe River surface water (~40%). Aquifer water is naturally filtered through limestone and requires minimal treatment; surface water treated at the H2Oaks Center. Supplemented by aquifer storage and recovery (ASR) during drought. One of the largest Edwards Aquifer users in the state.

68

Fair

0 EPA violations
6 above EWG guideline

Score methodology →
EPA · TX0150018UCMR5 PFAS data included1,095,000 people servedLast updated Nov 2025
EPA UCMR5 · November 2025EPA SDWIS · December 2024

Fair — with 6 concerns

San Antonio Water System (Saws) meets all federal legal limits but 6 contaminants exceed EWG health guidelines. Lead levels within limits at treatment plant

Lead levels within limits at treatment plantAll contaminants within federal legal limits

Personalise for your household

Select all that apply

Lead—source matters

Lead in tap water comes from household plumbing, not the source water or treatment plant. San Antonio water leaves the treatment plant lead-free. Risk depends on your building's internal plumbing—highest in homes built before 1986, when lead solder was common. A NSF/ANSI 53 certified pitcher or under-sink filter removes lead at point of use.

Source water—blended supply

San Antonio Water System (Saws) blends surface water and local groundwater. The figures above reflect utility-wide averages across all distribution zones. Water chemistry—particularly hardness, nitrates, and naturally occurring minerals—can vary meaningfully by district and season depending on the blend ratio. If your neighbourhood draws primarily from the groundwater portion, contaminant levels for minerals and agricultural compounds may differ from the utility average shown here.

Source: Edwards Aquifer karst groundwater (~60% of supply) blended with Guadalupe River surface water (~40%). Aquifer water is naturally filtered through limestone and requires minimal treatment; surface water treated at the H2Oaks Center. Supplemented by aquifer storage and recovery (ASR) during drought. One of the largest Edwards Aquifer users in the state.

Contaminants tested

32 total · 6 above EWG guideline
ContaminantLevelStatus
28.3 ppb
Above guideline
16.8 ppb
Above guideline
7.5 ppt
Above guideline
Nitrate

CAS 14797-55-8

3.4 ppm
Above guideline
3.2 ppt
Above guideline
Arsenic

CAS 7440-38-2

1.4 ppb
Above guideline
3.8 ppt
Within limits
Lithium

CAS 7439-93-2

15.8 ppb
Within limits
Fluoride

CAS 16984-48-8

0.70 ppm
Within limits
Lead

CAS 7439-92-1

1.6 ppb
Within limits
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
ND
Not detected
LegendWithin limitsAbove EWG guidelineAbove EPA limitNot detectedSource: EPA SDWIS · UCMR5 · EWG Health Guidelines

Filter recommendation

6 contaminants above guidelines. Here's what removes them.

A guided 4-question flow matches you to the right filter for your setup, budget, and household.

Get filter match →
Water wellness · Drawn Health

Want to go further than filtration?

Your report shows 6 contaminants above health guidelines. A specialist at Drawn can give you an expert read on your specific profile — what to prioritise, which filters actually address it, and what optimisation looks like for your household.

What a consultation covers

  • Your contaminant profile explained in plain English
  • Filter recommendations matched to what's actually in your water
  • Optimisation options for households ready for that conversation
Talk to a specialist at Drawn

20 min · Free · No obligation

Data sources

EPA UCMR5 (PFAS + lithium)·November 2025·One-time programme 2023–2025
EPA SDWIS compliance data·December 2024·Annual reporting cycle

Status flags compare detected levels against both EPA legal limits and EWG health-based guidelines—which are stricter and science-derived, independent of political feasibility.