Casa Diablo Hot Pool

Mono County, California · Near Mammoth Lakes
37.6470°N, 118.8590°W · 7,070 ft
165°F 34°F air · Good soaking weather 7,070 ft Open Short Walk CITY Camping nearby (4.5 mi)
Very Hot Source, Use Extreme Caution

At 165°F, the source water at Casa Diablo Hot Pool is hot enough to cause burns. Some hot springs this hot have cooler side pools or downstream areas suitable for soaking. Always test the water temperature before entering.

Aerial view of the ground around Casa Diablo Hot Pool LiDAR bare-earth view of the same ground around Casa Diablo Hot Pool
Aerial LiDAR bare earth

Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.

Casa Diablo Hot Pool is a scalding thermal pool in Mono County, about seven miles from Mammoth Lakes, on ground owned by LADWP, the Los Angeles water and power utility. The water would burn you. Access is open, but this is a feature to look at. A 1992 USGS sample found it heavy in dissolved minerals, with iron among them.

Location

Around seventy-one hundred feet, high desert, with roughly seven feet of snow a year and modest rain. Whatever road gets closest goes unnamed here, roughly five hundred feet off; the access class is short walk. LADWP ground, a utility's holding, with no park or forest status attached. Sherwin Creek is the campground on file, four miles and change.

Winter months listed, snow included. Camp at Sherwin Creek if you need to. The water scalds; keep away from the edge. The chemistry is from 1992 and the temperature reading carries no date, so neither should be taken as current. No fee is on record.

Terrain

Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around Casa Diablo Hot Pool.

Setting
Gentle slope
The ground tilts gently up to the north.
Highest ground nearby
257 ft above the spring
Within a quarter mile, to the north
Cross-section through the spring

A slice through the ground from north to south, about 0.6 miles end to end.

Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.

Heat Below
132 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 82% of the springs on this site.

Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.

Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.

Monthly Climate
30°
Jan
28°
Feb
33°
Mar
39°
Apr
47°
May
60°
Jun
67°
Jul
66°
Aug
60°
Sep
49°
Oct
38°
Nov
28°
Dec
Annual Precip: 16.2 in Annual Snow: 83.6 in
Best Time to Visit
February Air 28°F · Water 165°F · +137° contrast
December Air 28°F · Water 165°F · +137° contrast
January Air 30°F · Water 165°F · +135° contrast
February offers 39°F more contrast than July
Current Conditions
34°F
N 0.0 mph 51% Good soaking weather
Today 75° Low 39° Sunny
Spring is +90° warmer
Wednesday 72° Low 37° Sunny
Spring is +93° warmer
Thursday 71° Low 38° Sunny
Spring is +94° warmer
Friday 73° Low 40° Sunny
Spring is +92° warmer
Saturday 74° Low 42° Sunny 1% precip
Spring is +91° warmer
Water Chemistry Sampled 1992-04-15

The water at Casa Diablo Hot Pool is slightly alkaline (pH 7.7) with 1230 mg/L total dissolved solids. It is notably rich in sodium (supports circulation and skin hydration), chloride (natural antiseptic with skin health benefits), and total dissolved solids (higher mineral concentration for therapeutic soaking).

pH 7.7 Slightly Alkaline
pH influences mineral absorption through skin
Higher mineral concentration for therapeutic soaking
Calcium 7 mg/L
May support bone density and joint health
Magnesium 0 mg/L
Known for muscle relaxation and stress relief
Sodium 350 mg/L
Supports circulation and skin hydration
Sulfate 110 mg/L
Traditionally used for skin conditions and inflammation
Chloride 240 mg/L
Natural antiseptic with skin health benefits
Iron 5 µg/L
Iron-rich springs may support circulation
Nearby Camping
Nearby Camping
Sherwin Creek 4.5 mi away

Overview Sherwin Creek Campground is located in the eastern Sierra Nevada Mountains within 2 miles of the full-service community of Mammoth Lakes, California. Popular among anglers, hikers, off-road vehicle enthusiasts and photographers, the campground is near some of the most spectacular wilderness and outdoor recreation areas in the Sierras.Recreation With a motocross track and trails, Sherwin Creek is a hot spot for off-road vehicle enthusiasts. The area's majestic scenery and challenging...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 7,070 ft

Casa Diablo Hot Pool sits at 7,070 feet above sea level, way above the mile-high mark. You may not feel the altitude strongly, but hot water still dehydrates you faster at elevation. UV is about 28% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
165°F
Warm Hot Boiling
Water Temp 165°F (74°C)
Avg Air Temp 46°F
Above Ambient +119°F
Great soaking conditions September
Access
Open
Road Access Short Walk
Distance to Road 508 ft
Land
Ownership Local
Agency CITY
Designation LOTH
Unit Los Angeles Department of Water and Power
Manager CITY
Protection 4 - No known protection
Frequently Asked Questions
What is the water temperature at Casa Diablo Hot Pool?
Casa Diablo Hot Pool has a water temperature of 165°F (74°C). This is considered a hot spring, well above body temperature.
Where is Casa Diablo Hot Pool located?
Casa Diablo Hot Pool is located in Mono County, California at 7,070 feet elevation, near Mammoth Lakes. Coordinates: 37.6470°N, 118.8590°W.
How do I get to Casa Diablo Hot Pool?
Casa Diablo Hot Pool has Short Walk road access (508 ft from the road).
Is Casa Diablo Hot Pool free to visit?
Casa Diablo Hot Pool has Open access. It is managed by CITY.
Can I camp near Casa Diablo Hot Pool?
Yes, Sherwin Creek is located nearby (4.5 miles away).
What minerals are in the water at Casa Diablo Hot Pool?
Water chemistry analysis shows the presence of pH, Total Dissolved Solids, Calcium, Magnesium, Sodium, Sulfate, Chloride, Iron. The pH is 7.7 (slightly alkaline). Total dissolved solids measure 1,230 mg/L.
Is it safe to soak at Casa Diablo Hot Pool?
No, not at the source. The water at Casa Diablo Hot Pool reaches 165°F, which can cause severe burns within seconds. Look for cooled side pools or downstream stretches, and test with a hand before anything else.
Sources: USGS NWIS