Nitrate
East Lyme Water & Sewer Commission
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
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 1.12 ppm | 74 | 74 | 0.0300 ppm - 3.73 ppm |
| 2019 | 0.994 ppm | 147 | 147 | 0.0200 ppm - 3.94 ppm |
| 2020 | 1.78 ppm | 4 | 4 | 0.520 ppm - 3.18 ppm |
| 2021 | 1.51 ppm | 5 | 5 | 0.270 ppm - 3.32 ppm |
| 2022 | 0.949 ppm | 15 | 15 | 0.280 ppm - 3.47 ppm |
| 2023 | 0.968 ppm | 85 | 85 | 0.240 ppm - 3.84 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
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 |
|---|---|---|
| 2018-02-12 | 115996GE | 0.560 ppm |
| 2018-02-12 | 115997GE | 3.73 ppm |
| 2018-02-12 | 115998GE | 0.360 ppm |
| 2018-02-12 | 115999GE | 3.25 ppm |
| 2018-02-12 | 116000GE | 1.52 ppm |
| 2018-02-12 | 116001GE | 1.08 ppm |
| 2018-09-13 | CB30532 | 0.800 ppm |
| 2018-09-13 | CB30533 | 0.460 ppm |
| 2018-09-13 | CB30534 | 0.0300 ppm |
| 2018-09-13 | CB30535 | 1.60 ppm |
| 2018-09-13 | CB30536 | 1.70 ppm |
| 2018-09-13 | CB30537 | 0.340 ppm |
| 2018-09-13 | CB30538 | 0.870 ppm |
| 2018-09-13 | CB30539 | 1.39 ppm |
| 2018-09-24 | CB37210 | 0.930 ppm |
| 2018-09-24 | CB37211 | 0.440 ppm |
| 2018-09-24 | CB37212 | 0.0800 ppm |
| 2018-09-24 | CB37213 | 1.71 ppm |
| 2018-09-24 | CB37214 | 1.78 ppm |
| 2018-09-24 | CB37215 | 0.560 ppm |
| 2018-09-24 | CB37216 | 0.320 ppm |
| 2018-09-24 | CB37217 | 1.38 ppm |
| 2018-09-24 | CB37218 | 3.46 ppm |
| 2018-10-10 | CB68932 | 0.740 ppm |
| 2018-10-10 | CB68933 | 0.430 ppm |
| 2018-10-10 | CB68934 | 1.52 ppm |
| 2018-10-10 | CB68935 | 1.65 ppm |
| 2018-10-10 | CB68936 | 1.74 ppm |
| 2018-10-10 | CB68937 | 0.280 ppm |
| 2018-10-10 | CB68938 | 0.340 ppm |
| 2018-10-10 | CB68939 | 1.24 ppm |
| 2018-10-30 | CB84625 | 0.970 ppm |
| 2018-10-30 | CB84626 | 0.510 ppm |
| 2018-10-30 | CB84627 | 0.680 ppm |
| 2018-10-30 | CB84628 | 0.600 ppm |
| 2018-10-30 | CB84629 | 1.02 ppm |
| 2018-10-30 | CB84630 | 0.450 ppm |
| 2018-10-30 | CB84631 | 0.390 ppm |
| 2018-10-30 | CB84632 | 3.34 ppm |
| 2018-11-08 | CB90712 | 0.880 ppm |
| 2018-11-08 | CB90713 | 0.430 ppm |
| 2018-11-08 | CB90714 | 0.560 ppm |
| 2018-11-08 | CB90715 | 0.410 ppm |
| 2018-11-08 | CB90716 | 1.75 ppm |
| 2018-11-08 | CB90717 | 0.310 ppm |
| 2018-11-08 | CB90718 | 0.330 ppm |
| 2018-11-08 | CB90719 | 3.02 ppm |
| 2018-11-28 | CC03994 | 0.850 ppm |
| 2018-11-28 | CC03995 | 0.410 ppm |
| 2018-11-28 | CC03996 | 0.0900 ppm |
| 2018-11-28 | CC03997 | 0.570 ppm |
| 2018-11-28 | CC03998 | 1.26 ppm |
| 2018-11-28 | CC03999 | 1.23 ppm |
| 2018-11-28 | CC04000 | 0.330 ppm |
| 2018-11-28 | CC04001 | 2.00 ppm |
| 2018-11-28 | CC04002 | 3.03 ppm |
| 2018-12-05 | CC07654 | 0.740 ppm |
| 2018-12-05 | CC07655 | 0.400 ppm |
| 2018-12-05 | CC07656 | 0.150 ppm |
| 2018-12-05 | CC07657 | 1.64 ppm |
| 2018-12-05 | CC07658 | 1.55 ppm |
| 2018-12-05 | CC07659 | 0.740 ppm |
| 2018-12-05 | CC07660 | 1.84 ppm |
| 2018-12-05 | CC07661 | 0.700 ppm |
| 2018-12-05 | CC07662 | 3.38 ppm |
| 2018-12-18 | 121900 | 1.01 ppm |
| 2018-12-19 | CC17059 | 1.23 ppm |
| 2018-12-19 | CC17060 | 0.370 ppm |
| 2018-12-19 | CC17061 | 0.400 ppm |
| 2018-12-19 | CC17062 | 1.59 ppm |
| 2018-12-19 | CC17063 | 1.77 ppm |
| 2018-12-19 | CC17064 | 1.28 ppm |
| 2018-12-19 | CC17065 | 1.42 ppm |
| 2018-12-19 | CC17066 | 0.840 ppm |
| 2019-01-14 | CC28221 | 0.750 ppm |
| 2019-01-14 | CC28222 | 0.530 ppm |
| 2019-01-14 | CC28223 | 0.760 ppm |
| 2019-01-14 | CC28224 | 0.700 ppm |
| 2019-01-14 | CC28225 | 1.72 ppm |
| 2019-01-14 | CC28226 | 1.000 ppm |
| 2019-01-14 | CC28227 | 0.790 ppm |
| 2019-01-14 | CC28228 | 1.47 ppm |
| 2019-01-14 | CC28229 | 1.09 ppm |
| 2019-01-24 | CC33680 | 0.910 ppm |
| 2019-01-24 | CC33681 | 0.550 ppm |
| 2019-01-24 | CC33682 | 0.850 ppm |
| 2019-01-24 | CC33683 | 1.75 ppm |
| 2019-01-24 | CC33684 | 1.77 ppm |
| 2019-01-24 | CC33685 | 0.780 ppm |
| 2019-01-24 | CC33686 | 1.55 ppm |
| 2019-01-24 | CC33687 | 2.81 ppm |
| 2019-02-14 | CC51802 | 0.930 ppm |
| 2019-02-14 | CC51803 | 0.660 ppm |
| 2019-02-14 | CC51804 | 0.780 ppm |
| 2019-02-14 | CC51805 | 1.73 ppm |
| 2019-02-14 | CC51806 | 1.67 ppm |
| 2019-02-14 | CC51807 | 1.21 ppm |
| 2019-02-14 | CC51808 | 0.700 ppm |
| 2019-02-14 | CC51809 | 1.01 ppm |
| 2019-02-14 | CC51810 | 2.24 ppm |
| 2019-02-27 | CC58577 | 1.01 ppm |
| 2019-02-27 | CC58578 | 0.720 ppm |
| 2019-02-27 | CC58579 | 0.900 ppm |
| 2019-02-27 | CC58580 | 1.58 ppm |
| 2019-02-27 | CC58581 | 1.54 ppm |
| 2019-02-27 | CC58582 | 0.360 ppm |
| 2019-02-27 | CC58583 | 0.430 ppm |
| 2019-02-27 | CC58584 | 3.33 ppm |
| 2019-03-13 | CC66808 | 0.900 ppm |
| 2019-03-13 | CC66809 | 0.650 ppm |
| 2019-03-13 | CC66810 | 0.950 ppm |
| 2019-03-13 | CC66811 | 0.770 ppm |
| 2019-03-13 | CC66812 | 1.51 ppm |
| 2019-03-13 | CC66813 | 0.450 ppm |
| 2019-03-13 | CC66814 | 0.710 ppm |
| 2019-03-13 | CC66815 | 3.31 ppm |
| 2019-03-27 | CC75825 | 0.870 ppm |
| 2019-03-27 | CC75826 | 0.670 ppm |
| 2019-03-27 | CC75827 | 1.27 ppm |
| 2019-03-27 | CC75828 | 0.670 ppm |
| 2019-03-27 | CC75829 | 1.53 ppm |
| 2019-03-27 | CC75830 | 0.470 ppm |
| 2019-03-27 | CC75831 | 0.430 ppm |
| 2019-03-27 | CC75832 | 0.400 ppm |
| 2019-03-27 | CC75833 | 3.94 ppm |
| 2019-04-08 | CC90295 | 0.950 ppm |
| 2019-04-08 | CC90296 | 0.680 ppm |
| 2019-04-08 | CC90297 | 1.03 ppm |
| 2019-04-08 | CC90298 | 1.69 ppm |
| 2019-04-08 | CC90299 | 1.70 ppm |
| 2019-04-08 | CC90300 | 0.530 ppm |
| 2019-04-08 | CC90301 | 0.480 ppm |
| 2019-04-08 | CC90302 | 0.550 ppm |
| 2019-04-08 | CC90303 | 2.90 ppm |
| 2019-04-25 | CD01330 | 0.830 ppm |
| 2019-04-25 | CD01331 | 0.560 ppm |
| 2019-04-25 | CD01332 | 1.17 ppm |
| 2019-04-25 | CD01333 | 1.000 ppm |
| 2019-04-25 | CD01334 | 0.990 ppm |
| 2019-04-25 | CD01335 | 0.500 ppm |
| 2019-04-25 | CD01336 | 0.510 ppm |
| 2019-04-25 | CD01337 | 1.47 ppm |
| 2019-05-13 | CD11460 | 0.900 ppm |
| 2019-05-13 | CD11461 | 0.500 ppm |
| 2019-05-13 | CD11462 | 0.800 ppm |
| 2019-05-13 | CD11463 | 0.510 ppm |
| 2019-05-13 | CD11464 | 1.51 ppm |
| 2019-05-13 | CD11465 | 0.510 ppm |
| 2019-05-13 | CD11466 | 0.400 ppm |
| 2019-05-13 | CD11467 | 1.07 ppm |
| 2019-05-13 | CD11468 | 0.930 ppm |
| 2019-05-30 | CD23250 | 0.890 ppm |
| 2019-05-30 | CD23251 | 0.540 ppm |
| 2019-05-30 | CD23252 | 0.840 ppm |
| 2019-05-30 | CD23253 | 1.62 ppm |
| 2019-05-30 | CD23254 | 1.20 ppm |
| 2019-05-30 | CD23255 | 0.620 ppm |
| 2019-05-30 | CD23256 | 0.400 ppm |
| 2019-05-30 | CD23257 | 0.820 ppm |
| 2019-05-30 | CD23258 | 1.64 ppm |
| 2019-06-13 | CD33710 | 0.790 ppm |
| 2019-06-13 | CD33711 | 0.530 ppm |
| 2019-06-13 | CD33712 | 1.19 ppm |
| 2019-06-13 | CD33713 | 1.57 ppm |
| 2019-06-13 | CD33714 | 1.09 ppm |
| 2019-06-13 | CD33715 | 0.400 ppm |
| 2019-06-13 | CD33716 | 0.470 ppm |
| 2019-06-13 | CD33717 | 0.980 ppm |
| 2019-06-26 | CD42346 | 0.780 ppm |
| 2019-06-26 | CD42347 | 0.450 ppm |
| 2019-06-26 | CD42348 | 0.990 ppm |
| 2019-06-26 | CD42349 | 1.62 ppm |
| 2019-06-26 | CD42350 | 1.53 ppm |
| 2019-06-26 | CD42351 | 0.460 ppm |
| 2019-06-26 | CD42352 | 1.09 ppm |
| 2019-07-11 | CD54682 | 0.940 ppm |
| 2019-07-11 | CD54683 | 0.540 ppm |
| 2019-07-11 | CD54684 | 0.0700 ppm |
| 2019-07-11 | CD54685 | 1.08 ppm |
| 2019-07-11 | CD54686 | 1.74 ppm |
| 2019-07-11 | CD54687 | 0.420 ppm |
| 2019-07-11 | CD54688 | 0.890 ppm |
| 2019-07-24 | CD63751 | 0.860 ppm |
| 2019-07-24 | CD63743 | 0.680 ppm |
| 2019-07-24 | CD63744 | 0.420 ppm |
| 2019-07-24 | CD63745 | 0.190 ppm |
| 2019-07-24 | CD63746 | 1.75 ppm |
| 2019-07-24 | CD63747 | 1.88 ppm |
| 2019-07-24 | CD63748 | 0.630 ppm |
| 2019-07-24 | CD63749 | 0.440 ppm |
| 2019-08-07 | CD79747 | 0.830 ppm |
| 2019-08-07 | CD79748 | 0.470 ppm |
| 2019-08-07 | CD79749 | 0.0500 ppm |
| 2019-08-07 | CD79750 | 1.74 ppm |
| 2019-08-07 | CD79751 | 2.12 ppm |
| 2019-08-07 | CD79752 | 0.760 ppm |
| 2019-08-07 | CD79753 | 0.390 ppm |
| 2019-08-07 | CD79754 | 0.500 ppm |
| 2019-08-27 | CD92884 | 0.690 ppm |
| 2019-08-27 | CD92885 | 0.400 ppm |
| 2019-08-27 | CD92886 | 0.0200 ppm |
| 2019-08-27 | CD92887 | 0.320 ppm |
| 2019-08-27 | CD92888 | 1.03 ppm |
| 2019-08-27 | CD92889 | 0.390 ppm |
| 2019-08-27 | CD92890 | 0.920 ppm |
| 2019-08-28 | CD93750 | 0.520 ppm |
| 2019-08-28 | CD93751 | 0.870 ppm |
| 2019-09-10 | 127386 | 0.520 ppm |
| 2019-09-10 | 127387 | 2.39 ppm |
| 2019-09-10 | 127388 | 0.480 ppm |
| 2019-09-11 | CE06376 | 0.760 ppm |
| 2019-09-11 | CE06377 | 0.420 ppm |
| 2019-09-11 | CE06378 | 0.0300 ppm |
| 2019-09-11 | CE06379 | 0.440 ppm |
| 2019-09-11 | CE06380 | 1.74 ppm |
| 2019-09-11 | CE06381 | 0.460 ppm |
| 2019-09-11 | CE06382 | 0.390 ppm |
| 2019-09-11 | CE06384 | 1.06 ppm |
| 2019-12-09 | 129289 | 2.96 ppm |
| 2019-12-09 | 129290 | 1.08 ppm |
| 2019-12-23 | 129567 | 1.60 ppm |
| 2020-03-17 | 131055 | 1.95 ppm |
| 2020-03-17 | 131056 | 0.520 ppm |
| 2020-03-17 | 131057 | 3.18 ppm |
| 2020-03-17 | 131058 | 1.45 ppm |
| 2021-12-15 | CJ98853 | 1.78 ppm |
| 2021-12-15 | CJ98855 | 0.270 ppm |
| 2021-12-15 | CJ98858 | 3.32 ppm |
| 2021-12-15 | CJ98860 | 1.58 ppm |
| 2021-12-15 | CJ98841 | 0.610 ppm |
| 2022-03-16 | 146299 | 1.73 ppm |
| 2022-03-16 | 146300 | 0.410 ppm |
| 2022-03-16 | 146301 | 3.47 ppm |
| 2022-03-16 | 146302 | 0.750 ppm |
| 2022-05-17 | CL31858 | 0.310 ppm |
| 2022-05-17 | CL31861 | 0.700 ppm |
| 2022-05-17 | CL31862 | 0.720 ppm |
| 2022-05-17 | CL31863 | 0.720 ppm |
| 2022-05-17 | CL31864 | 1.77 ppm |
| 2022-05-17 | CL31865 | 1.56 ppm |
| 2022-05-17 | CL31866 | 0.280 ppm |
| 2022-05-17 | CL31867 | 0.290 ppm |
| 2022-05-17 | CL31868 | 0.770 ppm |
| 2022-05-17 | CL31869 | 0.300 ppm |
| 2022-09-27 | 151656 | 0.460 ppm |
| 2023-01-24 | 154936 | 1.79 ppm |
| 2023-01-24 | 154931 | 1.79 ppm |
| 2023-01-24 | 154932 | 0.310 ppm |
| 2023-01-24 | 154937 | 0.310 ppm |
| 2023-01-24 | 154938 | 3.23 ppm |
| 2023-01-24 | 154933 | 3.23 ppm |
| 2023-01-24 | 154934 | 0.830 ppm |
| 2023-01-24 | 154939 | 0.830 ppm |
| 2023-01-24 | 154940 | 0.740 ppm |
| 2023-01-24 | 154935 | 0.740 ppm |
| 2023-09-12 | 162967P | 0.820 ppm |
| 2023-09-12 | 162968P | 0.440 ppm |
| 2023-09-12 | 162974P | 0.820 ppm |
| 2023-09-12 | 162975P | 0.850 ppm |
| 2023-09-12 | 162976P | 1.20 ppm |
| 2023-09-12 | 162977P | 1.23 ppm |
| 2023-09-12 | 162978R | 0.460 ppm |
| 2023-09-12 | 162979P | 0.660 ppm |
| 2023-09-12 | 162980P | 0.410 ppm |
| 2023-09-27 | 163520 | 0.810 ppm |
| 2023-09-27 | 163522 | 0.910 ppm |
| 2023-09-27 | 163524 | 1.22 ppm |
| 2023-09-27 | 163526 | 1.19 ppm |
| 2023-09-27 | 163528 | 1.61 ppm |
| 2023-09-27 | 163530 | 0.640 ppm |
| 2023-09-27 | 163532 | 0.400 ppm |
| 2023-09-27 | 163534 | 2.16 ppm |
| 2023-09-27 | 163536 | 0.810 ppm |
| 2023-09-27 | 163538 | 0.430 ppm |
| 2023-10-11 | 164076 | 0.820 ppm |
| 2023-10-11 | 164078 | 0.990 ppm |
| 2023-10-11 | 164080 | 1.22 ppm |
| 2023-10-11 | 164082 | 1.20 ppm |
| 2023-10-11 | 164084 | 0.410 ppm |
| 2023-10-11 | 164086 | 0.460 ppm |
| 2023-10-11 | 164088 | 0.420 ppm |
| 2023-10-11 | 164090 | 0.820 ppm |
| 2023-10-11 | 164092 | 0.810 ppm |
| 2023-10-11 | 164094 | 0.410 ppm |
| 2023-10-25 | 164507 | 0.840 ppm |
| 2023-10-25 | 164509 | 1.17 ppm |
| 2023-10-25 | 164511 | 1.19 ppm |
| 2023-10-25 | 164513 | 1.07 ppm |
| 2023-10-25 | 164515 | 0.750 ppm |
| 2023-10-25 | 164517 | 0.410 ppm |
| 2023-10-25 | 164519 | 3.84 ppm |
| 2023-10-25 | 164521 | 0.820 ppm |
| 2023-10-25 | 164523 | 0.500 ppm |
| 2023-11-15 | 165296 | 0.840 ppm |
| 2023-11-15 | 165298 | 0.250 ppm |
| 2023-11-15 | 165300 | 1.22 ppm |
| 2023-11-15 | 165302 | 1.03 ppm |
| 2023-11-15 | 165304 | 0.990 ppm |
| 2023-11-15 | 165306 | 0.590 ppm |
| 2023-11-15 | 165308 | 0.420 ppm |
| 2023-11-15 | 165310 | 3.57 ppm |
| 2023-11-15 | 165312 | 0.810 ppm |
| 2023-11-15 | 165314 | 0.410 ppm |
| 2023-11-29 | 165735 | 0.870 ppm |
| 2023-11-29 | 165737 | 0.240 ppm |
| 2023-11-29 | 165739 | 0.510 ppm |
| 2023-11-29 | 165741 | 1.26 ppm |
| 2023-11-29 | 165743 | 0.590 ppm |
| 2023-11-29 | 165745 | 0.430 ppm |
| 2023-11-29 | 165747 | 0.420 ppm |
| 2023-11-29 | 165749 | 0.870 ppm |
| 2023-11-29 | 165751 | 0.440 ppm |
| 2023-12-07 | 166133 | 0.840 ppm |
| 2023-12-07 | 166135 | 0.260 ppm |
| 2023-12-07 | 166137 | 0.860 ppm |
| 2023-12-07 | 166139 | 1.20 ppm |
| 2023-12-07 | 166141 | 1.67 ppm |
| 2023-12-07 | 166143 | 1.86 ppm |
| 2023-12-07 | 166145 | 1.25 ppm |
| 2023-12-07 | 166147 | 0.840 ppm |
| 2023-12-07 | 166149 | 0.940 ppm |
| 2023-12-27 | 166776 | 0.870 ppm |
| 2023-12-27 | 166778 | 1.13 ppm |
| 2023-12-27 | 166780 | 1.24 ppm |
| 2023-12-27 | 166782 | 1.56 ppm |
| 2023-12-27 | 166784 | 0.430 ppm |
| 2023-12-27 | 166786 | 0.430 ppm |
| 2023-12-27 | 166788 | 0.860 ppm |
| 2023-12-27 | 166790 | 0.850 ppm |
| 2023-12-27 | 166792 | 0.440 ppm |