Is Houston tap water safe to drink?
In the latest results, every contaminant we list with a single federal limit was below that limit or action level. Lead was 5 ppb at the 90th percentile, below the 15 ppb action level. EPA’s goal for lead is zero. Lithium was found above EPA’s health reference level (10 ppb), a screening value that is not an enforceable limit. EPA lists 1 health-based violation in the last 10 years, the latest in May 2025. See how US tap water compares nationally.
What’s in Houston tap water
Latest results from Houston Public Works’ 2025 report and EPA records. One row per contaminant, with the type of limit in the limit column.
| Contaminant | Result | Limit | Sampled | Source |
|---|---|---|---|---|
| LeadComes mostly from home plumbing, not from the source water. | 5 ppb 90th percentile reported to EPA; previous round (Jul – Dec 2023): 3 ppb | 15 ppbAction level · goal 0Drops to 10 ppb on Nov 1, 2027 (Lead and Copper Rule Improvements). | Jan – Jun 2024 | EPA SDWIS record, TX1010013 |
| PFOA and PFOS (PFAS)Two “forever chemicals” with a federal limit. | Not detected 96 samples at 39 entry points; none at or above the reporting level (4 ppt) | 4.0 ppt eachLegal limit (MCL) · goal 0Utilities must comply from 2029; EPA proposed 2031 in May 2026. | Feb 2023 – Feb 2025 | EPA UCMR 5 final occurrence data (Aug 2026 release) |
| Other PFASFound among the 27 other PFAS EPA had utilities test. | 4 found 6:2 FTS up to 42.6 ppt; PFBA up to 10.6 ppt; PFPeA up to 6.7 ppt; PFHxA up to 5.1 ppt | VariesSet per compound in EPA’s PFAS rule | Feb 2023 – Feb 2025 | EPA UCMR 5 final occurrence data (Aug 2026 release) |
| Nitrate (as N)From fertilizer runoff and septic systems. | Up to 1.4 mg/L Average 0.35 mg/L | 10 mg/LLegal limit (MCL) · goal 10 | 2025 | City of Houston 2025 Water Quality Report |
| Total trihalomethanesByproducts of disinfection. | 43.6 ppb Highest locational running annual average; range ND–47.7 | 80 ppbLegal limit (MCL) | 2025 | City of Houston 2025 Water Quality Report |
| Haloacetic acids (HAA5)Byproducts of disinfection. | 40.8 ppb Highest locational running annual average; range ND–55.9 | 60 ppbLegal limit (MCL) | 2025 | City of Houston 2025 Water Quality Report |
| Chloramine (as total chlorine)Disinfectant kept in the pipes on purpose. | 2.8 mg/L Average; range 0.04–4.8 | 4.0 mg/LDisinfectant limit (MRDL) · goal 4 | 2025 | City of Houston 2025 Water Quality Report |
| LithiumUnregulated; EPA is collecting national data. | Up to 33.9 ppb Found in 69 of 96 samples at 39 entry points; range 9.1–33.9 | 10 ppbEPA health reference levelA health reference level is a screening value, not an enforceable limit. | Feb 2023 – Feb 2025 | EPA UCMR 5 final occurrence data (Aug 2026 release) |
ppb = parts per billion (µg/L), ppt = parts per trillion (ng/L). The bar shows the result against the limit (black line). Limits: EPA drinking water regulations, PFAS rule, Lead and Copper Rule Improvements. “Not detected” means below the lab’s reporting level, not zero.
EPA violations
EPA’s SDWIS database lists 3 violation records for Houston Public Works since 2015, 1 of them health-based. All have a return-to-compliance date.
Not listed: 1 older monitoring, reporting or notice record (2015), none health-based.
Shown: health-based violations and everything from the last 10 years. Source: EPA SDWIS record, TX1010013, retrieved Oct 13, 2026.
How hard is Houston water?
The utility’s figures cover the whole system. To test the hardness at your tap, strips or a drop kit take minutes.
Classes: USGS (0–60 mg/L soft, 61–120 moderately hard, 121–180 hard, above 180 very hard). 1 gpg = 17.1 mg/L as calcium carbonate. Source: City of Houston 2025 Water Quality Report.
What to do with these numbers
Only what the data above points to.
Lead comes from home plumbing
EPA’s goal for lead is zero. Older faucets, lead solder and lead service lines can add lead at your tap. A filter certified to NSF/ANSI 53 for lead reduces it.
Certified to reduce lead. Lead is not necessarily in your water.
All filters compared →Hard water
Above 120 mg/L (7.1 gpg) USGS calls water hard. Hardness has no federal health limit, but it leaves scale in kettles, water heaters and on fixtures. Filters for lead or chloramine do not reduce it. A water softener at the main line does.
Whole-house systems compared →Chloramine taste and smell
Houston Public Works disinfects with chloramine on purpose, below the 4.0 mg/L limit. If you dislike the taste, look for a filter certified to NSF/ANSI 42 for chloramine. For home dialysis and aquariums it must be reduced first.
Certified to reduce chloramine.
Under-sink filters compared →Test your own water
Houston Public Works’ numbers come from its own sampling sites. A certified lab test of your faucet shows lead and copper from your plumbing and the chloramine level at your tap. How to test your own tap for lead, starting with your water utility.
All water tests compared →