Bexar County’s water supply primarily comes from aquifer 218EDRD, drawing from depths between 340 and 596 feet. Groundwater from this aquifer travels through natural underground rock formations before reaching household taps, where its properties, including pH, influence water quality and appliance longevity.
Belief: Existing treatment systems always meet the household’s daily acidic water demand
Households often assume their current equipment fully addresses acidic water at all times. However, when demand exceeds treatment capacity, water can remain acidic despite existing systems. Judging whether treatment keeps pace requires understanding daily water use patterns and comparing them with the system’s documented capability to neutralize or filter low-pH water. If your household’s daily requirement surpasses what your system can manage consistently, acidic water symptoms may persist.
Belief: A standard water test simply shows if water is acidic or not
Certified laboratory tests for pH report a numerical value reflecting acidity or alkalinity, usually between 0 and 14 standard units. Results near or below the EPA’s secondary standard low threshold of 6.5 suggest acidic water with potential for aesthetic issues like metallic taste or staining. However, a single test does not reveal fluctuations or depth-based variations affecting household water. Reading test results involves comparing values to these benchmarks and considering the timing and sampling source.
Belief: Area median pH levels directly indicate individual household water acidity
The U.S. Geological Survey sampled three Bexar County wells, totaling 99 pH results from 2010 to 2026. These readings ranged broadly from 5.4 to 8.3, with a median at 7.2 standard units. This median value generally aligns with neutral water, but some samples fell below the 6.5 level that indicates acidity. As these data come from multiple deep wells, they provide a regional picture, not an exact measure for each home. Homeowners should consider these figures as context rather than a direct reflection of their own water.
Belief: Well depth and source type do not influence household water pH
The depth of sampled wells in Bexar County ranged from 340 to 596 feet, a factor that can affect water chemistry. Deeper wells may draw water with different mineral balances or acidity levels than shallower sources. Additionally, aquifer characteristics and local geology influence pH variations over time and location, so households with wells at different depths or sources might experience differing acidic water challenges.
Belief: Household size and seasonal use do not affect acidic water treatment needs
Larger households or properties used seasonally may require treatment systems capable of handling variable water volumes and demand peaks. If treatment capacity is stretched during peak use, acidic water can bypass the system’s neutralizing effect. Similarly, second homes with irregular usage might face periods where untreated acidic water causes gradual impacts. Considering household size and usage patterns is essential when evaluating or upgrading treatment technologies.
Belief: Untreated acidic water causes immediate and severe water quality damage
While untreated acidic water can contribute over time to issues like metallic taste, staining of fixtures, or corrosion of pipes, these effects develop gradually rather than suddenly. The EPA secondary standard for pH (6.5–8.5) serves as an aesthetic guideline and does not indicate a health risk. Monitoring and managing acidic water helps maintain plumbing longevity and household water appeal but does not imply urgent danger.
What you should NOT conclude from Bexar County’s acidic water data
The regional pH data for aquifer 218EDRD offers insight into water quality trends but does not establish the exact conditions of any individual household’s water supply. A detection below or above certain pH values is not a regulatory violation or proof of unsafe water. Confirming your water’s acidity level requires a certified laboratory test of your own well or tap water. For households seeking enhanced management of low-pH water, the C-Series Acidic / Low-pH Water Filter ships ready to configure, designed specifically to address acidic water challenges documented in this region.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2026-06-01. These figures describe groundwater sampled in this area. They are not a test of any individual private well - only a test of that well can establish its own water.
On record: U.S. Geological Survey sampling of pH in the 218EDRD aquifer (Bexar County): 99 results from 3 wells, median 7.2 standard units, range 5.4-8.3 standard units; EPA secondary standard for pH is 6.5-8.5 (aesthetic/corrosivity, not health-based); 1 of 99 sampled results fell below 6.5