EWG's Tap Water Database — 2021 UPDATE



City of Llano

Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20140.130 ppm110.130 ppm
20150.0800 ppm110.0800 ppm
20160.175 ppm220.170 ppm - 0.180 ppm
20170.140 ppm110.140 ppm
20180.0600 ppm110.0600 ppm
20190.660 ppm110.660 ppm

ppm = parts per million

State and national drinking water standards and health guidelines

EWG Health Guideline 0.14 ppm

The EWG Health Guideline of 0.14 ppm for nitrate was defined by EWG . This health guideline protects against cancer and harm to fetal growth and development.

EPA Maximum Contaminant
Level (MCL) 10 ppm

The legal limit for nitrate, established in 1962, was developed to protect infants from acute methemoglobinemia, a life-threatening disorder of oxygen transport in the body. This limit does not fully protect against the risk of cancer and harm to the developing fetus.

ppm = parts per million

All test results

Date Lab ID Result
2014-08-13AC633350.130 ppm
2015-04-16AC885080.0800 ppm
2016-03-21AD295150.180 ppm
2016-03-21AD294950.170 ppm
2017-02-16AD709800.140 ppm
2018-02-06AE123750.0600 ppm
2019-02-07AE533490.660 ppm