Billy Clapp Lake
Grant County, Washington1,010 acresView mapDirections
Washington Ecology publishes the water-quality measurements for Billy Clapp Lake. Here is what has been measured.
- Impaired · Nuisance exotic species
- 54 ft max depth
- Public access
- Limited data
Billy Clapp Lake in Grant County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Water clarity: 16.4 ft visibility. Surface area: 1010 acres.
Billy Clapp Lake is a 1,010-acre lake in Grant County, Washington with an estimated average depth of about 54 feet. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, WA Ecology, last sampled 2022-07-19. Methodology: how these readings are compared.
What Billy Clapp Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.4 ft of visibility
- Boat launch1 documented ramp
- Big water1,010 acres
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Billy Clapp Lake is listed impaired under Clean Water Act §303(d) (IR 4C) for nuisance exotic species. Check local advisories before you swim.
Whether Billy Clapp Lake is safe to swim in today is a call for the Washington State Department of Ecology and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Billy Clapp Lake
These are the measurements Washington Ecology publishes for Billy Clapp Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 16.4 ft down. TSI 37.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading 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. | 37 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Billy Clapp Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~54 ft est.
Surface area
1,010 acres
Public access
Yes
Listed by Washington Ecology
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Washington has not published bathymetry for Billy Clapp Lake.
Lake Size & Watershed
Watershed (drainage) area
188 sq mi
HydroLAKES / HydroSHEDS
Shoreline
11.9 mi
HydroLAKES / HydroSHEDS
Elevation
1,322 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Billy Clapp LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Stays near Billy Clapp Lake
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Fishing Billy Clapp Lake
Reservoir Info (USACE NID)
Billy Clapp Lake is a man-made reservoir impounded by the Pinto Dam (completed 1948), built primarily for flood risk reduction on the Crab Creek-Offstream; earth-type dam, 130 ft tall and 1,900 ft long.
- Surface area
- 1,010 ac
- Normal storage
- 64,200 ac-ft
- Max storage
- 76,500 ac-ft
- Drainage area
- 191.66 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
All listed purposes: Flood Risk Reduction;Irrigation;Recreation.
Source: USACE National Inventory of Dams, NID ID WA00269 · Operator website
EPA Impairment Status
Billy Clapp Lake is officially listed as impaired under Clean Water Act §303(d) in the 2018 EPA reporting cycle (IR category 4C).
Causes of impairment
Designated uses not supporting: Aquatic life.
Source: EPA ATTAINS assessment unit WA17020014000568_001_001 · Official waterbody report
Nearby Lakes in Grant County
Frequently asked questions about Billy Clapp Lake
Where is Billy Clapp Lake?
- Billy Clapp Lake is a lake in Grant County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.
What is the water quality of Billy Clapp Lake?
- Billy Clapp Lake in Grant County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Water clarity: 16.4 ft visibility. Surface area: 1010 acres.
Is Billy Clapp Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Billy Clapp Lake is listed impaired under Clean Water Act §303(d) (IR 4C) for nuisance exotic species. Check local advisories before you swim.
How deep is Billy Clapp Lake?
- No published bathymetric survey covers Billy Clapp Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 54 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 1010 acres.
Are there boat ramps on Billy Clapp Lake?
- Billy Clapp Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Billy Clapp Lake. Public access is listed as yes.
Can I fish at Billy Clapp Lake?
- Billy Clapp 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 Washington's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
1 measurement from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Bureau of Reclamation
1119USBR_WQX1 sample · 2022
Analytical methods
- Zebra/Quagga Mussel APHA 10200G Modified
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory