Measured, not modelled

Well water hardness in Texas, by county

Measured well-water hardness for Texas, county by county: the median of laboratory hardness samples taken at real water wells, in grains per gallon and mg/L as CaCO3, with the number of wells behind every figure.

Most published hardness-by-county tables are estimates from municipal tap water. The figures below are different: they are medians of laboratory samples taken at water wells, from the public record, and every row says how many wells stand behind it. The same table qualifies every lead Hard Water Feed sells, so this page is also how you check our arithmetic — the full method is on the methodology page.

The scale

Ratings below use the Water Quality Association scale, in grains per gallon (gpg); 1 gpg is 17.1 mg/L as CaCO3.

Every measured county

Source: Texas Water Development Board — Groundwater Database (GWDB). TWDB Groundwater Database (GWDBDownload.zip). A county appears only when at least 3 distinct wells carry a laboratory hardness result; the 1 of Texas’s 254 counties not listed fall short of that bar, and it is left out rather than guessed at.

Is well water hard in Harris County, Texas?

Mostly not — the median of 3,352 laboratory hardness samples from 1,078 measured wells in Harris County is 3.4 grains per gallon (about 58 mg/L as CaCO3), which is “slightly hard” on the Water Quality Association scale. The middle half of those samples falls between 1.7 and 6.8 gpg, so individual wells vary widely around the median. Samples span 1922–2025. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Gaines County, Texas?

Yes — the median of 1,106 laboratory hardness samples from 863 measured wells in Gaines County is 21 grains per gallon (about 359 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 16.3 and 30 gpg, so individual wells vary widely around the median. Samples span 1938–2024. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Brown County, Texas?

Yes — the median of 926 laboratory hardness samples from 846 measured wells in Brown County is 25.7 grains per gallon (about 439 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 19.4 and 38.3 gpg, so individual wells vary widely around the median. Samples span 1937–2023. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Crockett County, Texas?

Yes — the median of 1,088 laboratory hardness samples from 809 measured wells in Crockett County is 16 grains per gallon (about 274 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 13.8 and 26.7 gpg, so individual wells vary widely around the median. Samples span 1939–2023. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Travis County, Texas?

Yes — the median of 1,845 laboratory hardness samples from 755 measured wells in Travis County is 18.9 grains per gallon (about 323 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 16.6 and 24 gpg, so individual wells vary widely around the median. Samples span 1903–2026. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Blanco County, Texas?

Yes — the median of 984 laboratory hardness samples from 635 measured wells in Blanco County is 23.3 grains per gallon (about 398 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 19.5 and 30.9 gpg, so individual wells vary widely around the median. Samples span 1938–2026. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in El Paso County, Texas?

Yes — the median of 4,236 laboratory hardness samples from 601 measured wells in El Paso County is 7.7 grains per gallon (about 132 mg/L as CaCO3), which is “hard” on the Water Quality Association scale. The middle half of those samples falls between 5.1 and 11.5 gpg, so individual wells vary widely around the median. Samples span 1926–2026. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Bexar County, Texas?

Yes — the median of 3,923 laboratory hardness samples from 569 measured wells in Bexar County is 16 grains per gallon (about 274 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 14 and 21.3 gpg, so individual wells vary widely around the median. Samples span 1913–2026. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Schleicher County, Texas?

Yes — the median of 723 laboratory hardness samples from 552 measured wells in Schleicher County is 14 grains per gallon (about 239 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. The middle half of those samples falls between 13 and 15.4 gpg, so individual wells vary widely around the median. Samples span 1941–2025. This is groundwater measured at other wells in the county, not a reading from any one property.

Is well water hard in Tarrant County, Texas?

Mostly not — the median of 987 laboratory hardness samples from 525 measured wells in Tarrant County is 0.7 grains per gallon (about 12 mg/L as CaCO3), which is “soft” on the Water Quality Association scale. The middle half of those samples falls between 0.5 and 3.2 gpg, so individual wells vary widely around the median. Samples span 1923–2023. This is groundwater measured at other wells in the county, not a reading from any one property.

The answers above cover the 10 counties with the most measured wells; the table covers every county that clears the minimum. If your county isn’t listed, the honest answer is that the public record doesn’t hold enough well samples there for us to say — not that its water is soft.

What this means if you sell water treatment

Hard Water Feed publishes a weekly feed of newly filed domestic wells in these counties, qualified against this same hardness table and sold to one water-treatment business per territory. The territory grid shows what’s open; the category guide explains the mechanism.

Built from the same data that builds the feed, and regenerated with it — figures on this page change only when the underlying public record does.