What was found in Redmond'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 | 1710 µg/L 17% of the EPA limit 10000 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019
Highest in the city: 1948 µg/L — AMES LAKE WATER ASSOC INC · 3,224 people · 2019 | 3/3 | SYR4 |
| Nitrate-Nitrite | 1710 µg/L 17% of the EPA limit 10000 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 3/3 | SYR4 |
| Fluoride | 830 µg/L 21% of the EPA limit 4000 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2017 | 1/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 43.78 µg/L 73% of the EPA limit 60 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 2/3 | SYR4 |
| TTHM | 40.48 µg/L 51% of the EPA limit 80 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 2/3 | SYR4 |
| Chloroform | 38.18 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 2/3 | SYR4 |
| Copper | 34 µg/L 2.6% of the EPA limit 1300 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2017 | 1/3 | SYR4 |
| Trichloroacetic Acid | 23.485 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 2/3 | SYR4 |
| Dichloroacetic Acid | 20.25 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 1/3 | SYR4 |
| Lithium | 13 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2024 | 1/3 | UCMR-5 |
| Bromodichloromethane | 6.1025 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 2/3 | SYR4 |
| Barium | 5 µg/L 0.3% of the EPA limit 2000 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2017 | 1/3 | SYR4 |
| Dibromochloromethane | 4.29 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 1/3 | SYR4 |
| Monochloroacetic Acid | 4.25 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 1/3 | SYR4 |
| Arsenic | 1.8 µg/L 18% of the EPA limit 10 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2017
Highest in the city: 3.95 µg/L — UNION HILL WATER ASSOCIATION INC · 8,720 people · 2018 | 3/3 | SYR4 |
| Lead | 3 µg/L 20% of the EPA limit 15 µg/L Highest in the city: AMES LAKE WATER ASSOC INC · 3,224 people · 2015 | 1/3 | SYR4 |
| Chromium | 2 µg/L 2% of the EPA limit 100 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2017 | 1/3 | SYR4 |
| Gross Beta Particle Activity | 1.575 pCi/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2016 | 1/3 | SYR4 |
| Dibromoacetic Acid | 1.444 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 1/3 | SYR4 |
| Tetrachloroethylene | 1.05 µg/L 21% of the EPA limit 5 µg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 1/3 | SYR4 |
| Bromoform | 1.0164 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2019 | 1/3 | SYR4 |
| Lead | 0.0020 mg/L 13% of the EPA limit 0.0150 mg/L Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2024
Highest in the city: 0.0058 mg/L — UNION HILL WATER ASSOCIATION INC · 8,720 people · 2025 | 3/3 | LCR |
| PFBS | 0.0050 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2024 | 1/3 | UCMR-5 |
| PFOS | 0.0050 µg/L No EPA limit set Main supplier: REDMOND WATER SYSTEM CITY OF · 163,335 people · 2024 | 1/3 | 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 Redmond
| Supplier | Population served |
|---|---|
| REDMOND WATER SYSTEM CITY OF | 163,335 |
| UNION HILL WATER ASSOCIATION INC | 8,720 |
| AMES LAKE WATER ASSOC INC | 3,224 |
Frequently asked questions about Redmond tap water
Is Redmond tap water safe to drink?
EPA testing detected 24 contaminants in the water serving Redmond. 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 Redmond?
3 public water suppliers report drinking-water monitoring for Redmond, Washington to the EPA. Each is listed above with its population served.
What contaminants are in Redmond's water?
The contaminants EPA monitoring detected in Redmond include Nitrate, Nitrate-Nitrite, Fluoride, Total Haloacetic Acids (HAA5), TTHM. 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.