Mckay Lake
Umatilla County, Oregon1,200 acresView mapDirections
Oregon DEQ publishes the water-quality measurements for Mckay Lake. Here is what has been measured.
- Impaired · Mercury
- Public access
- Limited data
Mckay Lake in Umatilla County, Oregon has water-quality measurements published by Oregon DEQ, shown here as reported. Water clarity: 3.3 ft visibility. Phosphorus: 121.5 µg/L. Chlorophyll-a (algae): 49.4 µg/L. Surface area: 1200 acres.
Mckay Lake is a 1,200-acre lake in Umatilla County, Oregon. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2020-06-15. Methodology: how these readings are compared.
Mckay Lake covers about 1,200 acres in Umatilla County. It has one public boat landing. If you are planning to stay, you can search lake houses and cabins around Mckay Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Mckay Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Big water1,200 acres
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Mckay Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury). Check local advisories before you swim.
Whether Mckay Lake is safe to swim in today is a call for the Oregon Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mckay Lake
These are the measurements Oregon DEQ publishes for Mckay Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3.3 ft of visibility. Phosphorus 121.5 µg/L. Chlorophyll-a 49.4 µg/L. TSI 67.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 122µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 49.4µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 67 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Mckay Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
1,200 acres
Public access
Yes
Listed by Oregon DEQ
No bathymetric survey has been published for Mckay Lake, so its depth is not documented here.
Recreation & Access
- McKay Creek (North)Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Mckay Lake
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Top-rated places to stay near Mckay Lake
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Fishing Mckay Lake
Water quality readings over time
3 seasons of samples on record (2020–2025). Calling a direction takes at least 4 years of the same measurement.
Chlorophyll-a
Improving-8.23 µg/L/yr3 years
Reservoir Info (USACE NID)
Mckay Lake is a man-made reservoir impounded by the Mckay Dam (completed 1927), built primarily for flood risk reduction on the Mckay Creek; earth-type dam, 165 ft tall and 2,700 ft long.
- Surface area
- 1,200 ac
- Normal storage
- 67,800 ac-ft
- Max storage
- 71,534 ac-ft
- Drainage area
- 193.24 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
All listed purposes: Flood Risk Reduction;Irrigation.
Source: USACE National Inventory of Dams, NID ID OR00583 · Operator website
EPA Impairment Status
Mckay Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit OR_LK_1707010304_02_100009 · Official waterbody report
Nearby Lakes in Umatilla County
Frequently asked questions about Mckay Lake
Where is Mckay Lake?
- Mckay Lake is a lake in Umatilla County, Oregon. Its water-quality measurements are published by Oregon DEQ and shown on this page as reported.
What is the water quality of Mckay Lake?
- Mckay Lake in Umatilla County, Oregon has water-quality measurements published by Oregon DEQ, shown here as reported. Water clarity: 3.3 ft visibility. Phosphorus: 121.5 µg/L. Chlorophyll-a (algae): 49.4 µg/L. Surface area: 1200 acres.
Is Mckay Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Mckay Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury). Check local advisories before you swim.
Are there boat ramps on Mckay Lake?
- Mckay Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include McKay Creek (North). Public access is listed as yes.
Can I fish at Mckay Lake?
- Mckay Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Oregon's fish and wildlife agency, so check its current regulations before you go.
Explore Mckay Lake across LakeQuality
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Where this data comes from
6 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Bureau of Reclamation
1119USBR_WQX6 samples · 2020
Analytical methods
- Zebra/Quagga Mussel APHA 10200G Modified
- Phosphorus by Single Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory