Is Mesa Water District Tap Water Safe? Quality Report

Water source: SWP
Ownership: Local government
Counties served: Orange

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

violations on file

still open

Violation	Type	Status	Period
MCL	Health-based	Resolved	2000-07-01 → 2000-07-31
MCL	Health-based	Resolved	2000-07-01 → 2000-07-31
MR	Monitoring	Resolved	2010-01-01 → 2015-12-31
MR	Monitoring	Resolved	2010-01-01 → 2015-12-31

Other contaminants detected

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 this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
TTHM	47.9 µg/L 60% of the EPA limit 80 µg/L worst single sample: 67 µg/L	243/251	SYR4	2012–2019
Bromoform	18 µg/L No EPA limit set worst single sample: 21 µg/L	231/251	SYR4	2012–2019
Chloroform	15.8 µg/L No EPA limit set worst single sample: 20 µg/L	225/251	SYR4	2012–2019
Dibromochloromethane	14 µg/L No EPA limit set worst single sample: 22 µg/L	223/251	SYR4	2012–2019
Bromodichloromethane	14 µg/L No EPA limit set worst single sample: 19 µg/L	220/251	SYR4	2012–2019
Dibromoacetic Acid	5.6 µg/L No EPA limit set worst single sample: 6.5 µg/L	211/248	SYR4	2012–2019
Total Haloacetic Acids (HAA5)	17.75 µg/L 30% of the EPA limit 60 µg/L worst single sample: 22 µg/L	206/248	SYR4	2012–2019
Dichloroacetic Acid	8.605 µg/L No EPA limit set worst single sample: 10 µg/L	134/248	SYR4	2012–2019
Nitrate	1586 µg/L 16% of the EPA limit 10000 µg/L worst single sample: 1850 µg/L	112/208	SYR4	2012–2019
Trichloroacetic Acid	6.11 µg/L No EPA limit set worst single sample: 6.6 µg/L	70/248	SYR4	2012–2019
Fluoride	850 µg/L 21% of the EPA limit 4000 µg/L worst single sample: 900 µg/L	56/56	SYR4	2012–2019
Nitrate-Nitrite	865500 µg/L 8655% of the EPA limit, at the 95th percentile of samples — 10000 µg/L worst single sample: 980000 µg/L	50/96	SYR4	2012–2019
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L	31/31	LCR	2023
Monobromoacetic Acid	4.055 µg/L No EPA limit set worst single sample: 4.9 µg/L	14/248	SYR4	2012–2019
Combined Uranium	3.14166 µg/L 10% of the EPA limit 30 µg/L worst single sample: 3.4121 µg/L	12/13	SYR4	2012–2017
Arsenic	2.65 µg/L 27% of the EPA limit 10 µg/L worst single sample: 2.8 µg/L	6/39	SYR4	2012–2019
Lithium	37.259 µg/L No EPA limit set	3/20	UCMR-5	2024
Combined Radium (-226 And -228)	0.5463 pCi/L 11% of the EPA limit 5 pCi/L worst single sample: 0.5610 pCi/L	2/2	SYR4	2012–2013
Gross Beta Particle Activity	1.87 pCi/L No EPA limit set worst single sample: 1.93 pCi/L	2/2	SYR4	2012–2013

92 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAtrazineBhc-GammaBariumBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCopperCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoLeadMercuryMethoxychlorMonochloroacetic AcidNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact: HERNANDEZ, JUAN
Phone: 949-207-5468
Email: [email protected]

Frequently asked questions about Mesa Water District

Is Mesa Water District tap water safe to drink?

EPA monitoring detected 19 contaminants in Mesa Water District's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Mesa Water District's water?

EPA monitoring detected TTHM, Bromoform, Chloroform, Dibromochloromethane, Bromodichloromethane, and others. The full list with the level and data source for each is above.

How many people does Mesa Water District serve?

Mesa Water District reports serving 110,000 people in California, per its EPA record.

Has Mesa Water District had any water quality violations?

The EPA has 4 violations on file for Mesa Water District, of which 2 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

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.