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EWG's Tap Water Database — 2021 UPDATE

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Nitrate

Montara Water and Sanitary District

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.

MORE ABOUT THIS CONTAMINANT

 

336

Samples

3

Samples exceeding legal limit (MCL)

199

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20143.81 ppm7049ND - 10.4 ppm
20152.76 ppm3522ND - 9.71 ppm
20162.70 ppm5331ND - 11.0 ppm
20172.77 ppm5931ND - 9.40 ppm
20182.63 ppm6232ND - 10.00 ppm
20192.71 ppm5734ND - 10.00 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
2014-01-235810-015-10058.13 ppm
2014-01-235810-015-14508.81 ppm
2014-01-235810-025-1005ND
2014-01-235810-025-1450ND
2014-01-235810-029-10054.29 ppm
2014-01-235810-029-14504.52 ppm
2014-03-185810-001-10108.81 ppm
2014-03-185810-008-10501.76 ppm
2014-03-245810-015-10459.71 ppm
2014-03-245810-015-14309.26 ppm
2014-03-245810-025-1100ND
2014-03-245810-025-1437ND
2014-03-245810-026-1110ND
2014-03-245810-029-11304.52 ppm
2014-03-245810-029-14425.42 ppm
2014-05-125810-001-12308.58 ppm
2014-05-125810-015-09409.26 ppm
2014-05-125810-015-12359.04 ppm
2014-05-125810-025-1010ND
2014-05-125810-025-1235ND
2014-05-125810-026-1040ND
2014-05-125810-026-1235ND
2014-05-125810-029-10202.94 ppm
2014-05-125810-029-12354.07 ppm
2014-05-135810-015-15009.49 ppm
2014-05-135810-025-1510ND
2014-05-135810-029-15204.07 ppm
2014-05-155810-015-11309.71 ppm
2014-05-155810-015-15409.49 ppm
2014-05-155810-025-1110ND
2014-05-155810-025-15201.13 ppm
2014-05-155810-029-11204.07 ppm
2014-05-155810-029-15304.07 ppm
2014-06-105810-015-08468.36 ppm
2014-06-105810-015-14468.81 ppm
2014-06-105810-025-0825ND
2014-06-105810-025-1430ND
2014-06-105810-029-08363.61 ppm
2014-06-105810-029-14384.97 ppm
2014-07-225810-015-08416.55 ppm
2014-07-225810-015-14257.23 ppm
2014-07-225810-025-0833ND
2014-07-225810-025-1415ND
2014-07-225810-029-08513.84 ppm
2014-07-225810-029-14354.29 ppm
2014-07-305810-026-0937ND
2014-08-275810-001-11409.04 ppm
2014-08-275810-011-09001.67 ppm
2014-08-275810-015-11209.94 ppm
2014-08-275810-025-1120ND
2014-08-275810-026-11200.678 ppm
2014-08-275810-029-11205.20 ppm
2014-10-201233-030-10200.149 ppm
2014-10-201233-031-1010ND
2014-10-201233-032-10250.149 ppm
2014-10-215810-015-121010.4 ppm
2014-10-215810-025-12101.08 ppm
2014-10-215810-026-12150.565 ppm
2014-10-215810-029-12154.52 ppm
2014-12-085810-001-11108.81 ppm
2014-12-085810-003-1110ND
2014-12-085810-012-10350.836 ppm
2014-12-085810-014-10300.565 ppm
2014-12-085810-015-11008.81 ppm
2014-12-085810-025-11109.94 ppm
2014-12-085810-026-1110ND
2014-12-085810-029-11104.07 ppm
2014-12-095810-008-10400.610 ppm
2014-12-095810-010-0955ND
2014-12-095810-011-10551.02 ppm
2015-03-095810-001-08409.26 ppm
2015-03-095810-015-08305.42 ppm
2015-03-095810-025-08300.587 ppm
2015-03-095810-026-0830ND
2015-03-095810-029-08302.71 ppm
2015-05-195810-001-10049.71 ppm
2015-05-195810-015-10205.65 ppm
2015-05-195810-025-10150.678 ppm
2015-05-195810-026-1015ND
2015-05-195810-029-10152.71 ppm
2015-08-045810-015-09005.42 ppm
2015-08-045810-025-09001.08 ppm
2015-08-045810-026-0905ND
2015-08-045810-029-09051.78 ppm
2015-08-175810-001-09208.10 ppm
2015-08-175810-001-09208.13 ppm
2015-08-175810-015-11005.20 ppm
2015-10-191233-030-0850ND
2015-10-191233-031-1050ND
2015-10-191233-031-1050ND
2015-10-191233-032-1015ND
2015-11-095810-001-11309.40 ppm
2015-11-095810-003-1200ND
2015-11-095810-010-1140ND
2015-11-095810-012-11200.600 ppm
2015-11-095810-014-11500.430 ppm
2015-11-095810-015-11404.10 ppm
2015-11-095810-025-1140ND
2015-11-095810-026-1140ND
2015-11-095810-029-11402.30 ppm
2015-11-235810-008-13452.50 ppm
2015-12-105810-015-10007.10 ppm
2015-12-105810-025-1000ND
2015-12-105810-026-1000ND
2015-12-105810-029-10003.60 ppm
2016-01-285810-011-09300.800 ppm
2016-02-115810-015-13356.40 ppm
2016-02-115810-025-1335ND
2016-02-115810-026-1335ND
2016-02-115810-029-13353.10 ppm
2016-03-025810-015-11109.30 ppm
2016-03-025810-025-1110ND
2016-03-025810-026-1110ND
2016-03-025810-029-11104.50 ppm
2016-03-145810-001-08409.00 ppm
2016-03-145810-015-085010.00 ppm
2016-03-145810-025-0905ND
2016-03-145810-026-0905ND
2016-03-145810-029-09055.10 ppm
2016-04-275810-015-092011.0 ppm
2016-04-275810-025-0922ND
2016-04-275810-026-09240.410 ppm
2016-04-275810-029-09265.80 ppm
2016-05-045810-015-095011.0 ppm
2016-05-045810-025-0950ND
2016-05-045810-026-09500.820 ppm
2016-05-045810-029-09506.60 ppm
2016-05-195810-010-1030ND
2016-06-225810-012-10000.580 ppm
2016-06-225810-015-10456.50 ppm
2016-06-225810-025-10450.920 ppm
2016-06-225810-026-1045ND
2016-06-225810-029-10452.70 ppm
2016-08-165810-015-09556.40 ppm
2016-08-165810-025-10003.00 ppm
2016-08-165810-026-1002ND
2016-08-165810-029-10052.90 ppm
2016-08-245810-025-0905ND
2016-08-245810-026-09050.430 ppm
2016-08-245810-029-09053.80 ppm
2016-09-305810-012-14300.520 ppm
2016-11-075810-001-09209.50 ppm
2016-11-075810-003-0930ND
2016-11-075810-008-09551.70 ppm
2016-11-075810-010-0935ND
2016-11-075810-012-10250.550 ppm
2016-11-075810-014-0925ND
2016-11-075810-015-09506.80 ppm
2016-11-075810-025-0950ND
2016-11-075810-026-0950ND
2016-11-075810-029-09503.40 ppm
2016-12-015810-015-09106.10 ppm
2016-12-015810-025-0910ND
2016-12-015810-026-0910ND
2016-12-015810-029-09103.30 ppm
2016-12-015810-031-1015ND
2016-12-015810-032-1035ND
2016-12-135810-030-1158ND
2017-01-185810-015-11209.40 ppm
2017-01-185810-025-1120ND
2017-01-185810-026-1120ND
2017-01-185810-029-11205.00 ppm
2017-01-255810-001-10509.10 ppm
2017-01-255810-008-09301.40 ppm
2017-02-135810-015-09089.00 ppm
2017-02-135810-025-09099.00 ppm
2017-02-135810-026-0910ND
2017-02-135810-029-0911ND
2017-03-205810-015-10587.40 ppm
2017-03-205810-025-1059ND
2017-03-205810-026-1100ND
2017-03-205810-029-11013.60 ppm
2017-04-115810-015-10357.50 ppm
2017-04-115810-025-1035ND
2017-04-115810-026-1035ND
2017-04-115810-029-10353.70 ppm
2017-05-095810-015-09006.70 ppm
2017-05-095810-025-0900ND
2017-05-095810-026-0900ND
2017-05-095810-029-09003.50 ppm
2017-06-065810-015-08407.20 ppm
2017-06-065810-025-0840ND
2017-06-065810-026-0840ND
2017-06-065810-029-08403.50 ppm
2017-07-055810-015-09407.00 ppm
2017-07-055810-025-0940ND
2017-07-055810-026-0940ND
2017-07-055810-029-09403.60 ppm
2017-08-075810-015-09157.50 ppm
2017-08-075810-025-0915ND
2017-08-075810-026-09150.410 ppm
2017-08-075810-029-09154.00 ppm
2017-09-065810-015-10057.30 ppm
2017-09-065810-025-1006ND
2017-09-065810-026-1007ND
2017-09-065810-029-10083.60 ppm
2017-10-105810-015-09207.10 ppm
2017-10-105810-025-0920ND
2017-10-105810-026-0920ND
2017-10-105810-029-09204.20 ppm
2017-11-095810-030-1120ND
2017-11-095810-031-1040ND
2017-11-095810-032-1130ND
2017-11-155810-003-0850ND
2017-11-155810-008-08550.950 ppm
2017-11-155810-010-0900ND
2017-11-155810-025-0834ND
2017-11-155810-026-0836ND
2017-11-155810-029-08303.60 ppm
2017-11-215810-012-11500.560 ppm
2017-11-215810-014-12150.430 ppm
2017-11-215810-015-11357.50 ppm
2017-12-075810-015-09006.70 ppm
2017-12-075810-025-0902ND
2017-12-075810-026-0904ND
2017-12-075810-029-09063.70 ppm
2017-12-275810-001-14359.40 ppm
2018-01-095810-015-09405.90 ppm
2018-01-095810-025-0940ND
2018-01-095810-026-0940ND
2018-01-095810-029-09403.10 ppm
2018-01-315810-001-09509.40 ppm
2018-01-315810-012-08500.700 ppm
2018-02-085810-015-10106.90 ppm
2018-02-085810-025-1012ND
2018-02-085810-026-1014ND
2018-02-085810-029-10163.70 ppm
2018-03-135810-015-09207.40 ppm
2018-03-135810-025-0920ND
2018-03-135810-026-0920ND
2018-03-135810-029-09203.90 ppm
2018-04-045810-015-08407.40 ppm
2018-04-045810-025-0840ND
2018-04-045810-026-0840ND
2018-04-045810-029-08404.00 ppm
2018-04-265810-001-11159.50 ppm
2018-04-265810-012-10150.610 ppm
2018-05-015810-015-08457.90 ppm
2018-05-015810-025-0845ND
2018-05-015810-026-0845ND
2018-05-015810-029-08454.20 ppm
2018-06-185810-015-08507.10 ppm
2018-06-185810-025-0850ND
2018-06-185810-026-0850ND
2018-06-185810-029-08503.70 ppm
2018-07-165810-015-10306.90 ppm
2018-07-165810-025-1030ND
2018-07-165810-026-1030ND
2018-07-165810-029-10303.70 ppm
2018-07-235810-001-113010.00 ppm
2018-07-235810-012-11100.730 ppm
2018-07-235810-015-11207.20 ppm
2018-08-025810-015-09007.10 ppm
2018-08-025810-025-0900ND
2018-08-025810-026-0900ND
2018-08-025810-029-09004.00 ppm
2018-09-115810-015-11106.30 ppm
2018-09-115810-025-1110ND
2018-09-115810-026-1110ND
2018-09-115810-029-11103.50 ppm
2018-10-155810-015-10105.80 ppm
2018-10-155810-025-1010ND
2018-10-155810-026-1010ND
2018-10-155810-029-10103.00 ppm
2018-11-135810-003-0900ND
2018-11-135810-008-09552.20 ppm
2018-11-135810-010-0930ND
2018-11-135810-014-0905ND
2018-11-135810-015-08305.70 ppm
2018-11-135810-025-0830ND
2018-11-135810-026-0830ND
2018-11-135810-029-08303.10 ppm
2018-11-155810-030-0900ND
2018-11-155810-031-0815ND
2018-11-155810-032-0835ND
2018-12-105810-015-09505.50 ppm
2018-12-105810-025-0950ND
2018-12-105810-026-0950ND
2018-12-105810-029-09502.70 ppm
2019-01-095810-015-09026.30 ppm
2019-01-095810-025-0905ND
2019-01-095810-026-0908ND
2019-01-095810-029-09113.20 ppm
2019-02-055810-015-10457.90 ppm
2019-02-055810-025-1045ND
2019-02-055810-026-1045ND
2019-02-055810-029-10454.20 ppm
2019-03-045810-015-08258.40 ppm
2019-03-045810-025-0826ND
2019-03-045810-026-0828ND
2019-03-045810-029-08304.70 ppm
2019-04-095810-015-08407.40 ppm
2019-04-095810-025-0840ND
2019-04-095810-026-08400.680 ppm
2019-04-095810-029-08404.30 ppm
2019-04-165810-010-1020ND
2019-05-155810-015-08206.00 ppm
2019-05-155810-025-0820ND
2019-05-155810-026-08200.560 ppm
2019-05-155810-029-08203.30 ppm
2019-06-035810-015-08549.20 ppm
2019-06-035810-025-0856ND
2019-06-035810-026-08580.610 ppm
2019-06-035810-029-09004.70 ppm
2019-07-095810-015-09456.50 ppm
2019-07-095810-025-09450.600 ppm
2019-07-095810-026-0945ND
2019-07-095810-029-09453.30 ppm
2019-08-065810-015-09106.30 ppm
2019-08-065810-025-09150.560 ppm
2019-08-065810-026-0917ND
2019-08-065810-029-09203.60 ppm
2019-09-175810-015-091010.00 ppm
2019-09-175810-025-0910ND
2019-09-175810-026-0910ND
2019-09-175810-029-09105.60 ppm
2019-10-145810-015-084010.00 ppm
2019-10-145810-025-08400.440 ppm
2019-10-145810-026-08400.530 ppm
2019-10-145810-029-08405.40 ppm
2019-10-165810-003-0910ND
2019-10-165810-008-09402.10 ppm
2019-10-165810-010-0905ND
2019-11-055810-030-1110ND
2019-11-055810-031-1100ND
2019-11-055810-032-1125ND
2019-11-135810-014-11000.420 ppm
2019-11-135810-015-10317.10 ppm
2019-11-135810-025-1032ND
2019-11-135810-026-1033ND
2019-11-135810-029-10343.00 ppm
2019-12-095810-015-10106.00 ppm
2019-12-095810-025-1010ND
2019-12-095810-026-1010ND
2019-12-095810-029-10102.70 ppm
2019-12-265810-001-08458.80 ppm