Know Your Environment. Protect Your Health.

Nitrate and nitrite

Regional Water Authority

Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. Click here to read more about nitrate.

 

232

Samples

0

Samples exceeding legal limit (MCL)

167

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20181.26 ppm27270.0900 ppm - 3.79 ppm
20191.48 ppm26260.0200 ppm - 3.80 ppm
20201.35 ppm29290.0340 ppm - 3.63 ppm
20211.11 ppm1151150.0140 ppm - 4.15 ppm
20220.258 ppm159ND - 1.16 ppm
20230.490 ppm2017ND - 3.47 ppm

ppm = parts per million

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.14 ppm

The EWG health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.

EPA Maximum Contaminant
Level (MCL): 10 ppm

ppm = parts per million

All test results

Date Lab ID Result
2018-03-12IOCR 2004897602.43 ppm
2018-03-12IOCR 2004897580.757 ppm
2018-03-12IOCR 2004897593.02 ppm
2018-03-14IOCR 2004899110.380 ppm
2018-03-14NOX 2004898672.47 ppm
2018-03-14NOX 2004898702.70 ppm
2018-03-14NOX 2004898681.04 ppm
2018-03-14NOX 2004898840.114 ppm
2018-03-14NOX 2004898850.270 ppm
2018-03-14NOX 2004898710.388 ppm
2018-03-14NOX 2004899130.414 ppm
2018-03-14NOX 2004899140.947 ppm
2018-03-14IOCR 2004898981.72 ppm
2018-03-14IOCR 2004899003.24 ppm
2018-03-14IOCR 2004898961.15 ppm
2018-03-14IOCR 2004899120.930 ppm
2018-03-14IOCR 2004898860.0900 ppm
2018-03-14IOCR 2004898870.240 ppm
2018-03-14IOCR 2004898720.373 ppm
2018-03-14IOCR 2004898970.972 ppm
2018-03-15NOX 2004900612.97 ppm
2018-03-15IOCR 2004900623.79 ppm
2018-03-15IOCR 2004900630.577 ppm
2018-03-23IOCR 2004905120.665 ppm
2018-11-29NOX 2005140970.872 ppm
2018-11-29NOX 2005141120.732 ppm
2018-11-29IOCR 2005141140.849 ppm
2019-03-18NOX 2005248951.17 ppm
2019-03-18IOCR 2005248963.37 ppm
2019-03-18IOCR 2005249033.80 ppm
2019-03-18IOCR 2005249011.31 ppm
2019-03-18IOCR 2005249023.07 ppm
2019-03-18IOCR 2005249050.981 ppm
2019-03-18IOCR 2005249001.48 ppm
2019-03-19IOCR 2005250950.526 ppm
2019-03-19NOX 2005250572.58 ppm
2019-03-19NOX 2005250603.72 ppm
2019-03-19NOX 2005250581.44 ppm
2019-03-19NOX 2005250593.10 ppm
2019-03-19NOX 2005250770.0200 ppm
2019-03-19NOX 2005250780.0510 ppm
2019-03-19NOX 2005250610.316 ppm
2019-03-19NOX 2005250970.491 ppm
2019-03-19NOX 2005250980.791 ppm
2019-03-19IOCR 2005250651.76 ppm
2019-03-19IOCR 2005250663.73 ppm
2019-03-19IOCR 2005250641.52 ppm
2019-03-19IOCR 2005250960.813 ppm
2019-03-19IOCR 2005250790.0480 ppm
2019-03-19IOCR 2005250800.0640 ppm
2019-03-19IOCR 2005250620.290 ppm
2019-05-08NOX 2005312970.986 ppm
2019-05-08IOCR 2005313031.01 ppm
2020-02-10NOX 2005654601.02 ppm
2020-02-10IOCR 2005654613.63 ppm
2020-02-10IOCR 2005654693.28 ppm
2020-02-10IOCR 2005654661.06 ppm
2020-02-10IOCR 2005654673.03 ppm
2020-02-10IOCR 2005654701.07 ppm
2020-02-11NOX 2005656242.69 ppm
2020-02-11NOX 2005656250.830 ppm
2020-02-11NOX 2005656272.98 ppm
2020-02-11NOX 200565625A0.830 ppm
2020-02-11NOX 2005656263.04 ppm
2020-02-11NOX 2005655930.0340 ppm
2020-02-11NOX 2005655940.193 ppm
2020-02-11NOX 200565628A0.257 ppm
2020-02-11NOX 2005656160.708 ppm
2020-02-11NOX 2005656171.11 ppm
2020-02-11IOCR 2005656321.66 ppm
2020-02-11IOCR 2005656333.37 ppm
2020-02-11IOCR 2005656312.77 ppm
2020-02-11NOX 2005656280.257 ppm
2020-02-11IOCR 2005655950.0350 ppm
2020-02-11IOCR 2005655960.179 ppm
2020-02-11IOCR 2005656290.243 ppm
2020-02-12IOCR 2005658470.646 ppm
2020-02-12IOCR 2005658480.884 ppm
2020-08-10IOCR 2005855970.629 ppm
2020-08-11NOX 2005857330.880 ppm
2020-08-11IOCR 2005857350.933 ppm
2020-08-11IOCR 2005857360.913 ppm
2021-02-08IOCR 2006058584.15 ppm
2021-02-08IOCR 2006058540.769 ppm
2021-02-08IOCR 2006058560.944 ppm
2021-02-08IOCR 2006058522.98 ppm
2021-02-08IOCR 2006058550.973 ppm
2021-02-09NOX 2006061143.73 ppm
2021-02-09NOX 2006061112.88 ppm
2021-02-09NOX 2006061100.920 ppm
2021-02-09NOX 2006061092.93 ppm
2021-02-09NOX 2006059561.27 ppm
2021-02-09NOX 2006058860.0820 ppm
2021-02-09NOX 2006058880.233 ppm
2021-02-09NOX 2006059591.23 ppm
2021-02-09IOCR 2006061153.31 ppm
2021-02-09IOCR 2006061122.64 ppm
2021-02-09IOCR 2006061133.23 ppm
2021-02-09IOCR 2006059571.32 ppm
2021-02-09IOCR 2006059580.961 ppm
2021-02-09IOCR 2006059311.13 ppm
2021-02-09NOX 2006061160.285 ppm
2021-02-09IOCR 2006058870.0540 ppm
2021-02-09IOCR 2006059601.28 ppm
2021-02-09IOCR 2006058890.209 ppm
2021-02-09IOCR 2006061170.268 ppm
2021-02-10IOCR 2006063591.41 ppm
2021-02-10IOCR 2006063560.843 ppm
2021-02-17IOCR 2006069100.367 ppm
2021-09-20N300062460 3000624630.0430 ppm
2021-09-20N300062466 3000624690.0400 ppm
2021-09-20N300062475 3000624780.0390 ppm
2021-09-20N300062500 3000625030.0430 ppm
2021-09-20N300062713 3000627160.0370 ppm
2021-09-20N300062724 3000627273.47 ppm
2021-09-20N300062698 3000627013.19 ppm
2021-09-20N300062683 3000626862.27 ppm
2021-09-20N300062689 3000626922.74 ppm
2021-09-20N300062662 3000626650.729 ppm
2021-09-20N300062674 3000626770.926 ppm
2021-09-20N300062652 3000626552.89 ppm
2021-09-20N300062668 3000626710.770 ppm
2021-09-21N300062817 3000628200.0440 ppm
2021-09-21N300062862 3000628650.0330 ppm
2021-09-21N300062874 3000628770.0360 ppm
2021-09-21N300062797 3000628002.64 ppm
2021-09-21N300062791 3000627942.43 ppm
2021-09-21N300062785 3000627880.960 ppm
2021-09-21N300062779 3000627822.85 ppm
2021-09-21N300062758 3000627610.971 ppm
2021-09-21N300062892 3000628950.0280 ppm
2021-09-21N300062905 3000629080.0500 ppm
2021-09-21N300062803 3000628060.0720 ppm
2021-09-21N300064199 3000642021.41 ppm
2021-09-21N300064205 3000642080.960 ppm
2021-09-21N300062764 3000627671.02 ppm
2021-09-21N300062770 3000627740.994 ppm
2021-09-21N300062898 3000629020.0140 ppm
2021-09-21N300062912 3000629160.0220 ppm
2021-09-21N300062810 3000628140.0510 ppm
2021-09-22N300064359 3000643620.0420 ppm
2021-09-22N300064371 3000643740.951 ppm
2021-09-22N300064777 3000647800.0260 ppm
2021-09-22N300064783 3000647860.0290 ppm
2021-09-22N300064789 3000647920.0420 ppm
2021-09-22N300064341 3000643443.55 ppm
2021-09-23N300066513 3000665160.377 ppm
2021-09-23N300066525 3000665281.80 ppm
2021-09-28N300068432 3000684350.0240 ppm
2021-09-29N300070521 3000705240.594 ppm
2021-10-18N300082865 3000828680.534 ppm
2021-10-18N300082872 3000828760.735 ppm
2021-12-06N300112518 3001125210.0370 ppm
2021-12-06N300112626 3001126290.0580 ppm
2021-12-06N300112635 3001126380.0330 ppm
2021-12-06N300112644 3001126470.0310 ppm
2021-12-06N300112669 3001126720.0320 ppm
2021-12-06N300112543 3001125463.53 ppm
2021-12-06N300112503 3001125063.32 ppm
2021-12-06N300112488 3001124912.32 ppm
2021-12-06N300112494 3001124973.03 ppm
2021-12-06N300112475 3001124783.20 ppm
2021-12-06N300112549 3001125520.581 ppm
2021-12-07N300112776 3001127790.0310 ppm
2021-12-07N300112788 3001127910.0310 ppm
2021-12-07N300113019 3001130220.0910 ppm
2021-12-07N300113213 3001132160.683 ppm
2021-12-07N300112999 3001130023.43 ppm
2021-12-07N300112992 3001129960.945 ppm
2021-12-07N300113807 3001138103.14 ppm
2021-12-07N300112806 3001128090.0340 ppm
2021-12-07N300112819 3001128220.158 ppm
2021-12-07N300113005 3001130080.111 ppm
2021-12-07N300113025 3001130300.618 ppm
2021-12-07N300113056 3001130593.31 ppm
2021-12-07N300113062 3001130650.902 ppm
2021-12-07N300112812 3001128160.0180 ppm
2021-12-07N300113034 3001130380.928 ppm
2021-12-07N300112826 3001128300.133 ppm
2021-12-07N300113012 3001130160.110 ppm
2021-12-07N300113068 3001130710.993 ppm
2021-12-08N300113983 3001139860.0290 ppm
2021-12-08N300113989 3001139920.0280 ppm
2021-12-08N300113995 3001139980.0300 ppm
2021-12-08N300114092 3001140952.17 ppm
2021-12-08N300114127 3001141300.106 ppm
2021-12-08N300114139 3001141422.73 ppm
2021-12-08N300114133 3001141361.42 ppm
2021-12-09N300115069 3001150720.325 ppm
2021-12-09N300116072 3001160751.32 ppm
2021-12-09N300116078 3001160811.47 ppm
2021-12-09N300116084 3001160871.06 ppm
2021-12-14N300113228 3001132310.746 ppm
2021-12-14N300113222 3001132250.767 ppm
2021-12-14N300113234 3001132371.05 ppm
2021-12-14N300113253 3001132560.302 ppm
2021-12-14N300113240 3001132431.08 ppm
2022-02-15N300145541 300145544ND
2022-02-15N300145532 300145535ND
2022-02-15N300145523 300145526ND
2022-02-15N300145514 300145517ND
2022-02-15N300146276 300146279ND
2022-02-15N300145647 3001456500.0340 ppm
2022-02-15N300145667 3001456700.308 ppm
2022-02-15N300145550 3001455530.180 ppm
2022-02-15N300145575 300145578ND
2022-02-15N300145699 3001457020.712 ppm
2022-02-15N300145718 3001457211.16 ppm
2022-02-15I300145657 3001456600.0390 ppm
2022-02-15I300145585 3001455880.964 ppm
2022-02-15I300145677 3001456800.286 ppm
2022-02-15I300145560 3001455630.186 ppm
2023-02-07I300305807 3003058100.0300 ppm
2023-05-09N300346683 300346686ND
2023-05-09N300346677 300346680ND
2023-05-09N300346671 3003466740.922 ppm
2023-05-09N300346754 3003467571.36 ppm
2023-05-09N300346689 3003466920.149 ppm
2023-05-09N300346708 3003467110.760 ppm
2023-05-09N300346714 3003467180.681 ppm
2023-05-09N300346695 3003466990.127 ppm
2023-05-10N300347601 3003476040.791 ppm
2023-05-10N300347613 3003476160.955 ppm
2023-05-23N300354085 300354088ND
2023-05-23N300354099 3003541020.1000 ppm
2023-05-23N300354092 3003540960.00500 ppm
2023-05-23N300354106 3003541100.0840 ppm
2023-08-15N300397643 3003976463.47 ppm
2023-08-15I300398155 3003981590.00800 ppm
2023-08-15I300397686 3003976900.271 ppm
2023-08-15I300398169 3003981730.0710 ppm
2023-08-15I300397667 3003976710.0150 ppm