Billy Clapp Lake
Grant County, Washington1,010 acresView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Impaired · Nuisance exotic species
- 54 ft max depth
- Public access
- Limited data
Billy Clapp Lake in Grant County, Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 16.4 ft visibility. Surface area: 1010 acres.
- Clarity
- 16.4 ft
- Max depth
- ~54 ft est.
- Area
- 1,010 acres
- Public access
- Yes
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Watch Billy Clapp Lake’s letter
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Why Billy Clapp Lake has no grade
Billy Clapp Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Billy Clapp Lake is Not Rated — not an F. Its 16.4-foot median from 1 readings collected 2022 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by WA Ecology and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
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. Grade methodology: LakeQuality methodology.
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 Safety
Not ratedLimited data
The letter is 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.
Water quality measurements for Billy Clapp Lake
These readings exist but are not enough for an A–F grade — see why.
Crystal clear, you can see 16.4 ft down. TSI 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.4 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~54 ft est. |
| Average Depth | ~25 ft est. |
| Surface Area | 1,010 acres |
| Public Access | Yes |
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
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
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
Source: EPA ATTAINS assessment unit WA17020014000568_001_001 · Official waterbody report
Graded lakes near Billy Clapp Lake
Billy Clapp Lake has no grade, but these lakes within a short drive do.
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. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Billy Clapp Lake?
- Billy Clapp Lake in Grant County, Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 16.4 ft visibility. Surface area: 1010 acres.
Is Billy Clapp Lake safe to swim in?
- The letter is 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.
Explore Billy Clapp Lake across LakeQuality
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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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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