← San Marcos, TX

Tap water quality report

ZIP 78667 — San Marcos, TX

EPA monitoring across the 1 water supplier serving ZIP 78667 in San Marcos, TX detected 31 contaminants. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier below, with the EPA limit for each.

1
water supplier
72,970
people served
31
contaminants found

What was found in ZIP 78667

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

ContaminantLevel vs EPA limitSuppliersSource
Nitrate-Nitrite
2172 µg/L 22%
of the EPA limit 10000 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2015
1/1 SYR4
Nitrate
1990.4999999999998 µg/L 20%
of the EPA limit 10000 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Fluoride
765 µg/L 19%
of the EPA limit 4000 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Chlorite
604 µg/L 60%
of the EPA limit 1000 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Copper
250.49999999999983 µg/L 19%
of the EPA limit 1300 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2018
1/1 SYR4
TTHM
88.075 µg/L 110%
of the EPA limit, at the 95th percentile of samples — 80 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Barium
46.76 µg/L 2.3%
of the EPA limit 2000 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
35.025 µg/L 58%
of the EPA limit 60 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Chloroform
27.58499999999998 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Bromodichloromethane
26.279999999999998 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Dibromochloromethane
23.95499999999999 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Dichloroacetic Acid
16.94999999999999 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Monochloroacetic Acid
12.319999999999993 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Lithium
11.3 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2024
1/1 UCMR-5
Cyanide
10 µg/L 5%
of the EPA limit 200 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Bromoform
8.6 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Trichloroacetic Acid
8.6 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Dibromoacetic Acid
6.369999999999998 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Lead
4.2 µg/L 28%
of the EPA limit 15 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2018
1/1 SYR4
Selenium
4.1 µg/L 8.2%
of the EPA limit 50 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Arsenic
2.2 µg/L 22%
of the EPA limit 10 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Monobromoacetic Acid
2.164999999999999 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Chromium
1.9595 µg/L 2%
of the EPA limit 100 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Combined Radium (-226 And -228)
1.5 pCi/L 30%
of the EPA limit 5 pCi/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2017
1/1 SYR4
Di(2-ethylhexyl) Phthalate
0.8700 µg/L 14%
of the EPA limit 6 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Antimony, Total
0.2220 µg/L 3.7%
of the EPA limit 6 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Atrazine
0.1600 µg/L 5.3%
of the EPA limit 3 µg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2019
1/1 SYR4
Pfba
0.0114 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2024
1/1 UCMR-5
Pfpea
0.0042 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2024
1/1 UCMR-5
PFHXS
0.0034 µg/L
No EPA limit set
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2024
1/1 UCMR-5
Lead
0.0016 mg/L 11%
of the EPA limit 0.0150 mg/L
Main supplier: CITY OF SAN MARCOS · 72,970 people · 2024
1/1 LCR
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.

Water suppliers serving ZIP 78667

SupplierStatePopulation served
CITY OF SAN MARCOS TX 72,970

Frequently asked questions about ZIP 78667 tap water

Is the tap water in ZIP 78667 safe to drink?

EPA testing detected 31 contaminants across the water suppliers serving ZIP 78667. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.

Which water suppliers serve ZIP 78667?

1 public water supplier report EPA drinking-water monitoring for ZIP 78667. Each is listed above with its population served.

What contaminants are in ZIP 78667's water?

EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Chlorite, Copper, and others across this ZIP's suppliers. The full list with levels and sources is above.