What was found in Thompson's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 859.5 µg/L 8.6% of the EPA limit 10000 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 4340 µg/L — THOMPSON HILL WATER CO - PAULA LANE DIV · 85 people · 2019 | 7/7 | SYR4 |
| Nitrate-Nitrite | 860 µg/L 8.6% of the EPA limit 10000 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 4084 µg/L — THOMPSON HILL WATER CO - PAULA LANE DIV · 85 people · 2019 | 7/7 | SYR4 |
| Fluoride | 130 µg/L 3.3% of the EPA limit 4000 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 1245.5 µg/L — CTWC - THOMPSON SYSTEM · 1,070 people · 2018 | 3/7 | SYR4 |
| Chlorite | 777 µg/L 78% of the EPA limit 1000 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 1/7 | SYR4 |
| Copper | 622 µg/L 48% of the EPA limit 1300 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 730 µg/L — CTWC - THOMPSON SYSTEM · 1,070 people · 2019 | 7/7 | SYR4 |
| TTHM | 120.44 µg/L 151% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 3/7 | SYR4 |
| Chloroform | 110 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 4/7 | SYR4 |
| Nitrite | 6.95 µg/L 0.7% of the EPA limit 1000 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 75.25 µg/L — QUINEBAUG MOBILE HOME PARK · 205 people · 2019 | 2/7 | SYR4 |
| Total Haloacetic Acids (HAA5) | 67 µg/L 112% of the EPA limit, at the 95th percentile of samples — 60 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 3/7 | SYR4 |
| Barium | 25.2 µg/L 1.3% of the EPA limit 2000 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 53.3 µg/L — CTWC - THOMPSON SYSTEM · 1,070 people · 2018 | 7/7 | SYR4 |
| Lead | 10.8 µg/L 72% of the EPA limit 15 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 35.5 µg/L — CTWC - THOMPSON SYSTEM · 1,070 people · 2019 | 7/7 | SYR4 |
| Dichloroacetic Acid | 34 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 3/7 | SYR4 |
| Trichloroacetic Acid | 33.1 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 2/7 | SYR4 |
| Arsenic | 1.3 µg/L 13% of the EPA limit 10 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 12.4 µg/L — QUINEBAUG MOBILE HOME PARK · 205 people · 2019 | 3/7 | SYR4 |
| Bromodichloromethane | 10.44 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 4/7 | SYR4 |
| Chromium | 7 µg/L 7% of the EPA limit 100 µg/L Highest in the city: THOMPSON HILL WATER CO - PAULA LANE DIV · 85 people · 2018 | 1/7 | SYR4 |
| Dibromochloromethane | 4.7 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 6.555 µg/L — JUSTICE RESOURCE INSTITUTE, INC. · 56 people · 2019 | 5/7 | SYR4 |
| Gross Alpha, Excl. Radon And U | 6.39 pCi/L 43% of the EPA limit 15 pCi/L Highest in the city: MARIANAPOLIS PREP SCHOOL - ST ALBERTS · 51 people · 2015 | 2/7 | SYR4 |
| Bromoform | 1.71 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 5.35 µg/L — JUSTICE RESOURCE INSTITUTE, INC. · 56 people · 2019 | 5/7 | SYR4 |
| Dibromoacetic Acid | 2.23 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019
Highest in the city: 4.46 µg/L — JUSTICE RESOURCE INSTITUTE, INC. · 56 people · 2019 | 3/7 | SYR4 |
| Monochloroacetic Acid | 3.835 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 2/7 | SYR4 |
| Combined Radium (-226 And -228) | 2.815 pCi/L 56% of the EPA limit 5 pCi/L Highest in the city: MARIANAPOLIS PREP SCHOOL - ST ALBERTS · 51 people · 2015 | 2/7 | SYR4 |
| P-Dichlorobenzene | 2.6795 µg/L 3.6% of the EPA limit 75 µg/L Highest in the city: MARIANAPOLIS PREP SCHOOL - ST JOHNS · 128 people · 2019 | 1/7 | SYR4 |
| Monobromoacetic Acid | 2.2 µg/L No EPA limit set Highest in the city: JUSTICE RESOURCE INSTITUTE, INC. · 56 people · 2019 | 1/7 | SYR4 |
| Antimony, Total | 2.1 µg/L 35% of the EPA limit 6 µg/L Highest in the city: THOMPSON HILL WATER CO - PAULA LANE DIV · 85 people · 2018 | 1/7 | SYR4 |
| Tetrachloroethylene | 0.9630 µg/L 19% of the EPA limit 5 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 1/7 | SYR4 |
| Di(2-ethylhexyl) Adipate | 0.6415 µg/L 0.2% of the EPA limit 400 µg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2019 | 1/7 | SYR4 |
| Styrene | 0.5700 µg/L 0.6% of the EPA limit 100 µg/L Highest in the city: THOMPSON HILL WATER CO - PAULA LANE DIV · 85 people · 2019 | 1/7 | SYR4 |
| PFOA | 0.0085 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2025 | 1/7 | UCMR-5 |
| PFOS | 0.0075 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2025 | 1/7 | UCMR-5 |
| Lead | 0.0028 mg/L 19% of the EPA limit 0.0150 mg/L Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2025
Highest in the city: 0.0074 mg/L — MARIANAPOLIS PREP SCHOOL - ST JOHNS · 128 people · 2025 | 7/7 | LCR |
| PFHXS | 0.0040 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2025 | 1/7 | UCMR-5 |
| PFBS | 0.0032 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2025 | 1/7 | UCMR-5 |
| Pfpea | 0.0031 µg/L No EPA limit set Main supplier: PUTNAM WATER POLLUTION CONTROL AUTHORITY · 7,300 people · 2025 | 1/7 | UCMR-5 |
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.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Thompson
| Supplier | Population served |
|---|---|
| PUTNAM WATER POLLUTION CONTROL AUTHORITY | 7,300 |
| CTWC - THOMPSON SYSTEM | 1,070 |
| QUINEBAUG MOBILE HOME PARK | 205 |
| MARIANAPOLIS PREP SCHOOL - ST JOHNS | 128 |
| THOMPSON HILL WATER CO - PAULA LANE DIV | 85 |
| JUSTICE RESOURCE INSTITUTE, INC. | 56 |
| MARIANAPOLIS PREP SCHOOL - ST ALBERTS | 51 |
Frequently asked questions about Thompson tap water
Is Thompson tap water safe to drink?
EPA testing detected 34 contaminants in the water serving Thompson. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Thompson?
7 public water suppliers report drinking-water monitoring for Thompson, Connecticut to the EPA. Each is listed above with its population served.
What contaminants are in Thompson's water?
The contaminants EPA monitoring detected in Thompson include Nitrate, Nitrate-Nitrite, Fluoride, Chlorite, Copper. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.