Is Houston, TX Tap Water Safe? Quality & Contaminants

What was found in Houston's water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

Contaminant	Level vs EPA limit	Suppliers	Source
Fluoride	538 µg/L 13% of the EPA limit 4000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 3329 µg/L — SHASLA PUD · 2,310 people · 2018	345/456	SYR4
Nitrate	780 µg/L 7.8% of the EPA limit 10000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 2770 µg/L — HARRIS COUNTY MUD 480 · 2,964 people · 2019	331/456	SYR4
Nitrate-Nitrite	310 µg/L 3.1% of the EPA limit 10000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 2696 µg/L — HARRIS COUNTY MUD 480 · 2,964 people · 2015	306/456	SYR4
Copper	338 µg/L 26% of the EPA limit 1300 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 2241.8 µg/L — BAYBROOK MUD 1 · 3,087 people · 2019	410/456	SYR4
Nitrite	36.5 µg/L 3.7% of the EPA limit 1000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 548.5 µg/L — HARRIS COUNTY FWSD 1A · 2,640 people · 2017	112/456	SYR4
Barium	365.4 µg/L 18% of the EPA limit 2000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 483.85 µg/L — HARRIS COUNTY MUD 215 · 2,541 people · 2017	346/456	SYR4
TTHM	49.635 µg/L 62% of the EPA limit 80 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 210.5 µg/L — BAYBROOK MUD 1 · 3,087 people · 2019	331/456	SYR4
Cyanide	93.5 µg/L 47% of the EPA limit 200 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 190 µg/L — JACKRABBIT ROAD PUD · 8,346 people · 2019	117/456	SYR4
Total Haloacetic Acids (HAA5)	49.97 µg/L 83% of the EPA limit 60 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 165.7 µg/L — BAYBROOK MUD 1 · 3,087 people · 2019	284/456	SYR4
Xylenes, Total	8.975 µg/L 0.1% of the EPA limit 10000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 152.885 µg/L — EL DORADO UTILITY DISTRICT · 3,591 people · 2019	96/456	SYR4
Chloroform	40.95 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 140.5 µg/L — BAYBROOK MUD 1 · 3,087 people · 2019	287/456	SYR4
Lead	10.74 µg/L 72% of the EPA limit 15 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 106.16 µg/L — NORTH PARK PUD · 6,708 people · 2019	375/456	SYR4
Dichloroacetic Acid	36.39 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 96.435 µg/L — BAYBROOK MUD 1 · 3,087 people · 2019	234/456	SYR4
Lithium	33.9 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2025 Highest in the city: 87.4 µg/L — NORTHWEST HARRIS COUNTY MUD 5 · 25,425 people · 2023	179/456	UCMR-5
Bromodichloromethane	12.9 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 69.825 µg/L — HARRIS COUNTY MUD 531 · 2,421 people · 2019	310/456	SYR4
Trichloroacetic Acid	12.33 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 48.71 µg/L — BAYBROOK MUD 1 · 3,087 people · 2019	201/456	SYR4
Combined Uranium	10.77 µg/L 36% of the EPA limit 30 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 48.4 µg/L — SUBURBAN MOBILE HOME PARK 2 · 120 people · 2016	144/456	SYR4
Gross Alpha, Excl. Radon And U	10.67 pCi/L 71% of the EPA limit 15 pCi/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 45.1 pCi/L — SUBURBAN MOBILE HOME PARK 2 · 120 people · 2016	190/456	SYR4
Bromoform	8.655 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 35.5 µg/L — MILLS ROAD MUD · 6,717 people · 2019	265/456	SYR4
Dibromochloromethane	5.2 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 35.055 µg/L — HARRIS COUNTY MUD 531 · 2,421 people · 2019	325/456	SYR4
Toluene	1 µg/L 0.1% of the EPA limit 1000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 34.23 µg/L — EL DORADO UTILITY DISTRICT · 3,591 people · 2019	22/456	SYR4
Gross Beta Particle Activity	7.23 pCi/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 27.5 pCi/L — SUBURBAN MOBILE HOME PARK 2 · 120 people · 2016	170/456	SYR4
Selenium	10.56 µg/L 21% of the EPA limit 50 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 24.2 µg/L — RENES WATER SYSTEM · 100 people · 2019	142/456	SYR4
Dibromoacetic Acid	3.43 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 19.62 µg/L — NORTHWEST HARRIS COUNTY MUD 5 · 25,425 people · 2019	227/456	SYR4
Ethylbenzene	2.075 µg/L 0.3% of the EPA limit 700 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 18.99 µg/L — NORTHWEST HARRIS COUNTY MUD 23 · 4,470 people · 2019	38/456	SYR4
Chromium	14.11 µg/L 14% of the EPA limit 100 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 17.2 µg/L — HARRIS COUNTY MUD 358 · 222 people · 2019	6/456	SYR4
Arsenic	7.08 µg/L 71% of the EPA limit 10 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 15.64 µg/L — HARRIS COUNTY MUD 11 · 3,645 people · 2019	234/456	SYR4
Monochloroacetic Acid	9.275 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 14.585 µg/L — HARRIS COUNTY MUD 49 · 10,893 people · 2019	170/456	SYR4
Di(2-ethylhexyl) Phthalate	1.58 µg/L 26% of the EPA limit 6 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 14.37 µg/L — HARRIS COUNTY FWSD 61 · 15,400 people · 2019	71/456	SYR4
Combined Radium (-226 And -228)	3.63 pCi/L 73% of the EPA limit 5 pCi/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 10.78 pCi/L — SUBURBAN MOBILE HOME PARK 2 · 120 people · 2016	245/456	SYR4
Monobromoacetic Acid	3.975 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 6.995 µg/L — BARKER CYPRESS MUD · 8,976 people · 2019	21/456	SYR4
Dalapon	4 µg/L 2% of the EPA limit 200 µg/L Highest in the city: NEWPORT MUD · 13,191 people · 2019	6/456	SYR4
Benzene	2.5 µg/L 50% of the EPA limit 5 µg/L Highest in the city: HARRIS COUNTY MUD 11 · 3,645 people · 2019	3/456	SYR4
Atrazine	0.4650 µg/L 16% of the EPA limit 3 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 2.3445 µg/L — CYPRESSWOOD UTILITY DISTRICT · 4,305 people · 2019	114/456	SYR4
2,4-D	1.355 µg/L 1.9% of the EPA limit 70 µg/L Highest in the city: NORTHWEST FREEWAY MUD · 3,678 people · 2017	10/456	SYR4
Antimony, Total	1 µg/L 17% of the EPA limit 6 µg/L Highest in the city: SUNBELT FWSD OAKWILDE SUBDIVISION · 6,819 people · 2019	1/456	SYR4
Carbon Tetrachloride	0.9000 µg/L 18% of the EPA limit 5 µg/L Highest in the city: HARRIS COUNTY MUD 167 · 16,761 people · 2019	3/456	SYR4
Dichloromethane	0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 0.7000 µg/L — KIRKMONT MUD · 2,277 people · 2017	3/456	SYR4
Di(2-ethylhexyl) Adipate	0.6600 µg/L 0.2% of the EPA limit 400 µg/L Highest in the city: MOUNT HOUSTON ROAD MUD · 5,346 people · 2019	1/456	SYR4
Pentachlorophenol	0.5700 µg/L 57% of the EPA limit 1 µg/L Highest in the city: HARRIS COUNTY WCID 114 · 5,160 people · 2017	1/456	SYR4
Vinyl Chloride	0.5000 µg/L 25% of the EPA limit 2 µg/L Highest in the city: HARRIS COUNTY MUD 196 · 7,026 people · 2019	1/456	SYR4
Benzo(A)Pyrene	0.0400 µg/L 20% of the EPA limit 0.2000 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 0.4000 µg/L — HARRIS COUNTY MUD 53 · 17,856 people · 2019	3/456	SYR4
Simazine	0.2030 µg/L 5.1% of the EPA limit 4 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 0.3200 µg/L — HARRIS COUNTY WCID 36 · 11,073 people · 2019	100/456	SYR4
Hexachlorocyclopentadiene	0.2150 µg/L 0.4% of the EPA limit 50 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 0.2245 µg/L — HARRIS COUNTY FWSD 51 · 19,671 people · 2019	14/456	SYR4
Methoxychlor	0.2100 µg/L 0.5% of the EPA limit 40 µg/L Highest in the city: HARRIS COUNTY MUD 130 · 4,572 people · 2019	2/456	SYR4
6:2 Fts	0.0426 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2025 Highest in the city: 0.1040 µg/L — FALLBROOK UTILITY DISTRICT · 6,720 people · 2024	4/456	UCMR-5
Picloram	0.1000 µg/L 0% of the EPA limit 500 µg/L Highest in the city: NORTHWEST HARRIS COUNTY MUD 36 · 3,648 people · 2019	1/456	SYR4
Pfba	0.0106 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2025 Highest in the city: 0.0504 µg/L — CHAMPIONS MUD · 4,098 people · 2023	89/456	UCMR-5
Bhc-Gamma	0.0500 µg/L 25% of the EPA limit 0.2000 µg/L Highest in the city: HARRIS COUNTY MUD 152 · 7,314 people · 2019	3/456	SYR4
Lead	0.0050 mg/L 33% of the EPA limit 0.0150 mg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2024 Highest in the city: 0.0438 mg/L — NORTHWEST HARRIS COUNTY MUD 9 · 7,848 people · 2026	440/456	LCR
Endrin	0.0100 µg/L 0.5% of the EPA limit 2 µg/L Main supplier: CITY OF HOUSTON · 2,970,543 people · 2019 Highest in the city: 0.0200 µg/L — HARRIS COUNTY MUD 196 · 7,026 people · 2019	2/456	SYR4
PFHXS	0.0153 µg/L No EPA limit set Highest in the city: SPENCER ROAD PUD · 5,607 people · 2024	22/456	UCMR-5
Pfpea	0.0067 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2025 Highest in the city: 0.0150 µg/L — HARRIS COUNTY MUD 230 · 10,404 people · 2023	94/456	UCMR-5
Pfhxa	0.0051 µg/L No EPA limit set Main supplier: CITY OF HOUSTON · 2,970,543 people · 2025 Highest in the city: 0.0107 µg/L — SPENCER ROAD PUD · 5,607 people · 2024	90/456	UCMR-5
PFOS	0.0097 µg/L No EPA limit set Highest in the city: SPENCER ROAD PUD · 5,607 people · 2024	5/456	UCMR-5
PFBS	0.0057 µg/L No EPA limit set Highest in the city: CLEAR LAKE CITY WATER AUTHORITY · 89,702 people · 2024	38/456	UCMR-5
Pfhpa	0.0048 µg/L No EPA limit set Highest in the city: SPENCER ROAD PUD · 5,607 people · 2024	2/456	UCMR-5
PFOA	0.0040 µg/L No EPA limit set Highest in the city: CLEAR LAKE CITY WATER AUTHORITY · 89,702 people · 2024	2/456	UCMR-5

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Houston

The 50 largest of 456 suppliers serving Houston, by population served.

Supplier	Population served
CITY OF HOUSTON	2,970,543
CLEAR LAKE CITY WATER AUTHORITY	89,702
CITY OF HOUSTON UD 5 - KINGWOOD	80,073
HARRIS COUNTY MUD 165	40,503
NORTHWEST HARRIS COUNTY MUD 5	25,425
BRIDGESTONE MUD	24,528
TIMBER LANE UTILITY DISTRICT	24,507
HARRIS COUNTY FWSD 51	19,671
CIMARRON MUD	19,338
HARRIS COUNTY MUD 82	18,990
NORTHWEST PARK MUD	18,168
CLEAR BROOK CITY MUD	18,108
HARRIS MONTGOMERY COUNTIES MUD 386	18,018
HARRIS COUNTY MUD 53	17,856
HARRIS COUNTY MUD 26	17,178
HARRIS COUNTY MUD 71	17,079
HARRIS COUNTY MUD 167	16,761
HARRIS COUNTY MUD 55 HERITAGE PARK	16,392
HARRIS COUNTY FWSD 61	15,400
HARRIS COUNTY MUD 105	14,925
HARRIS COUNTY MUD 200 CRANBROOK	14,868
HARRIS COUNTY MUD 24	14,796
CNP UTILITY DISTRICT	14,718
HARRIS COUNTY MUD 285	14,268
CITY OF HOUSTON WILLOW CHASE	14,169
MEADOWHILL REGIONAL MUD	13,863
REMINGTON MUD 1	13,746
HARRIS COUNTY MUD 120	13,197
NEWPORT MUD	13,191
HARRIS COUNTY MUD 157	13,062
HARRIS COUNTY MUD 1	12,342
NORTHAMPTON MUD	12,162
HARRIS COUNTY MUD 368	11,835
HARRIS COUNTY MUD 153	11,781
HARRIS COUNTY MUD 81	11,514
MEMORIAL VILLAGES WATER AUTHORITY	11,382
HARRIS COUNTY UD 6	11,262
HARRIS COUNTY WCID 36	11,073
CYPRESS HILL MUD 1	11,052
HARRIS COUNTY MUD 49	10,893
HARRIS COUNTY MUD 278	10,584
HARRIS COUNTY WCID 96	10,530
GREENWOOD UTILITY DISTRICT	10,527
HARRIS COUNTY MUD 489	10,476
HARRIS COUNTY MUD 230	10,404
HARRIS COUNTY MUD 102	10,401
LANGHAM CREEK UTILITY DISTRICT	10,377
MISSION BEND MUD 2	10,155
HARRIS COUNTY WCID 109	10,134
PONDEROSA FOREST UTILITY DISTRICT	10,101

Frequently asked questions about Houston tap water

Is Houston tap water safe to drink?

EPA testing detected 58 contaminants in the water serving Houston. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Houston?

456 public water suppliers report drinking-water monitoring for Houston, Texas to the EPA. Each is listed above with its population served.

What contaminants are in Houston's water?

The contaminants EPA monitoring detected in Houston include Fluoride, Nitrate, Nitrate-Nitrite, Copper, Nitrite. The full list, with the level at the main supplier and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.