Harris County, Texas has about 5,009,302 residents (Census 2024 estimate) and 714 community water systems in EPA records. The largest local system is City of Houston, serving about 2,970,543 people from surface water.
! 1 of 6 largest systems with health-based violationsPFAS detected at 5 of 6 sampled systemsHardness 7.9 gpg (high confidence)
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
How hard is Harris County water?
City of HoustonMeasured (utility report, 2025) · High confidence
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
Softener size at 7.9 gpg
For a 3-person home using 57 gallons per person per day and regenerating weekly, you'd remove about 9,456 grains between regenerations. Suggested size: 24,000 grain.
Estimate only. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
The 6 biggest of 714 community water systems on EPA records for this county. Service areas don't follow county lines; your water bill names your provider.
City of Houston
TX1010013 · serves about 2,970,543 people · Surface water
TX1010293 · serves about 152,000 people · Surface water
✓ No health-based violations✓ Lead below action levelPFAS detected (7 types)
Lead 90th percentile: 3.7 ppb (period starting 2022-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
PFBA: highest sample 12.7 ppt (12 of 24 samples); no federal limit
PFPeA: highest sample 8.4 ppt (15 of 24 samples); no federal limit
PFHxA: highest sample 7 ppt (15 of 24 samples); no federal limit
PFOS: highest sample 4.9 ppt (6 of 24 samples); federal limit 4.0 ppt as a running annual average
PFHxS: highest sample 4.3 ppt (8 of 24 samples); federal limit 10.0 ppt as a running annual average, also counted in EPA's PFAS mixture (hazard index) limit (currently in effect; EPA has proposed removing it)
PFBS: highest sample 3.5 ppt (7 of 24 samples); no individual limit; counted in EPA's PFAS mixture (hazard index) limit
PFHpA: highest sample 3.3 ppt (2 of 24 samples); no federal limit
TX1010056 · serves about 89,702 people · Surface water
✓ No health-based violations✓ Lead below action levelPFAS detected (8 types)
Lead 90th percentile: 0.9 ppb (period starting 2024-01-01). Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
PFBA: highest sample 14.5 ppt (14 of 18 samples); no federal limit
PFHxA: highest sample 9.5 ppt (15 of 18 samples); no federal limit
PFPeA: highest sample 8.8 ppt (15 of 18 samples); no federal limit
PFOS: highest sample 6.7 ppt (12 of 18 samples); federal limit 4.0 ppt as a running annual average
PFHxS: highest sample 6 ppt (12 of 18 samples); federal limit 10.0 ppt as a running annual average, also counted in EPA's PFAS mixture (hazard index) limit (currently in effect; EPA has proposed removing it)
PFBS: highest sample 5.7 ppt (12 of 18 samples); no individual limit; counted in EPA's PFAS mixture (hazard index) limit
PFOA: highest sample 4 ppt (1 of 18 samples); federal limit 4.0 ppt as a running annual average
PFHpA: highest sample 3.7 ppt (7 of 18 samples); no federal limit
TX1010003 · serves about 86,004 people · Surface water
✓ No health-based violations✓ Lead below action levelPFAS detected (7 types)
Lead 90th percentile: 2.1 ppb (period starting 2023-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
PFBA: highest sample 14.6 ppt (7 of 8 samples); no federal limit
PFPeA: highest sample 10.2 ppt (7 of 8 samples); no federal limit
PFHxA: highest sample 9.8 ppt (7 of 8 samples); no federal limit
PFOS: highest sample 6 ppt (7 of 8 samples); federal limit 4.0 ppt as a running annual average
PFBS: highest sample 5.7 ppt (6 of 8 samples); no individual limit; counted in EPA's PFAS mixture (hazard index) limit
PFHxS: highest sample 5.1 ppt (7 of 8 samples); federal limit 10.0 ppt as a running annual average, also counted in EPA's PFAS mixture (hazard index) limit (currently in effect; EPA has proposed removing it)
PFHpA: highest sample 3.7 ppt (4 of 8 samples); no federal limit
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
A PFAS detection is not a violation. Federal limits (4 ppt for PFOA and PFOS) apply to running annual averages, with compliance required by 2029. In May 2026 EPA proposed extending the PFOA/PFOS deadline to 2031 and removing other PFAS limits; not final as of 2026-10-21.
Test your own tap
These are public records for whole systems. Your home's pipes, fixtures and any private well can change what you drink. A certified lab test or a hardness test strip gives you your own numbers. Then use our PFAS and lead filter selector to see which certifications to look for.
Common questions about Harris County water
Is tap water in Harris County safe to drink?
1 of the 6 largest systems here have at least one health-based violation in EPA records since October 2021 (see each system below for status). City of Houston's most recent lead 90th percentile was 5 ppb (2024), below the 15 ppb action level. Public records can't guarantee what comes out of your tap, especially with older plumbing, so a home test is the surest check.
How hard is the water in Harris County?
City of Houston reports about 7.9 grains per gallon (136 mg/L), which is hard. For a 3-person home at 7.9 gpg, our softener calculator suggests a 24,000 grain unit as a starting point.
Is there PFAS in Harris County water?
5 of the 6 sampled systems listed here detected at least one PFAS in EPA's UCMR 5 testing, and 3 results were above the level of a federal limit in at least one sample. A detection isn't a violation: federal PFAS limits apply to running annual averages starting in 2029.
Which water system serves my address in Harris County?
Most homes are served by City of Houston or one of the other systems listed on this page, but service areas don't follow county lines. Your water bill names your provider, and its annual Consumer Confidence Report has the full test results.
Data as of October 21, 2026. Figures are copied from public records and combined with our own calculations; they can be out of date or wrong. Tapped Out isn't affiliated with any utility or the EPA. Written and reviewed by the Tapped Out team. How we calculate · All sources.