← Lake Oswego, OR

Tap water quality report

ZIP 97035 — Lake Oswego, OR

EPA monitoring across the 3 water suppliers serving ZIP 97035 in Lake Oswego, OR detected 12 contaminants. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier below, with the EPA limit for each.

3
water suppliers
710,200
people served
12
contaminants found

What was found in ZIP 97035

The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
376.5 µg/L 3.8%
of the EPA limit 10000 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
Highest in the ZIP: 2490 µg/L — RIVERGROVE WATER DISTRICT · 4,000 people · 2019
2/3 SYR4
Nitrate-Nitrite
324 µg/L 3.2%
of the EPA limit 10000 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
Highest in the ZIP: 2401.5 µg/L — RIVERGROVE WATER DISTRICT · 4,000 people · 2019
2/3 SYR4
Copper
402 µg/L 31%
of the EPA limit 1300 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
Highest in the ZIP: 778.75 µg/L — RIVERGROVE WATER DISTRICT · 4,000 people · 2019
3/3 SYR4
Fluoride
175 µg/L 4.4%
of the EPA limit 4000 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
1/3 SYR4
Total Haloacetic Acids (HAA5)
57.1 µg/L 95%
of the EPA limit 60 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
3/3 SYR4
TTHM
41.075 µg/L 51%
of the EPA limit 80 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
Highest in the ZIP: 43.43 µg/L — LAKE OSWEGO MUNICIPAL WATER · 40,000 people · 2019
2/3 SYR4
Lead
22.545 µg/L 150%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
3/3 SYR4
Barium
12.1 µg/L 0.6%
of the EPA limit 2000 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
1/3 SYR4
Lithium
12 µg/L
No EPA limit set
Highest in the ZIP: RIVERGROVE WATER DISTRICT · 4,000 people · 2025
1/3 UCMR-5
Arsenic
1.356 µg/L 14%
of the EPA limit 10 µg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2019
1/3 SYR4
Bromate
1.2 µg/L 12%
of the EPA limit 10 µg/L
Highest in the ZIP: LAKE OSWEGO MUNICIPAL WATER · 40,000 people · 2019
1/3 SYR4
Lead
0.0049 mg/L 33%
of the EPA limit 0.0150 mg/L
Main supplier: PORTLAND WATER BUREAU · 666,200 people · 2025
3/3 LCR
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.

Water suppliers serving ZIP 97035

SupplierStatePopulation served
PORTLAND WATER BUREAU OR 666,200
LAKE OSWEGO MUNICIPAL WATER OR 40,000
RIVERGROVE WATER DISTRICT OR 4,000

Frequently asked questions about ZIP 97035 tap water

Is the tap water in ZIP 97035 safe to drink?

EPA testing detected 12 contaminants across the water suppliers serving ZIP 97035. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.

Which water suppliers serve ZIP 97035?

3 public water suppliers report EPA drinking-water monitoring for ZIP 97035. Each is listed above with its population served.

What contaminants are in ZIP 97035's water?

EPA monitoring detected Nitrate, Nitrate-Nitrite, Copper, Fluoride, Total Haloacetic Acids (HAA5), and others across this ZIP's suppliers. The full list with levels and sources is above.