# Sulphur Works, Tophet Hot Springs, California

Sulphur Works, Tophet Hot Springs in California. 199°F (93°C). Roadside · Public Land. Plumas County.

- Page: https://www.soakingsprings.com/hot-springs/california/sulphur-works-tophet-hot-springs
- Source: Soaking Springs, researched and maintained by Armen Suny
- Updated: 2026-09-14

## Can you soak at Sulphur Works, Tophet Hot Springs?

Not at the source. The water leaves the ground at 199°F, hot enough to burn skin. You can drive right up to it. It's on National Park Service land.

## Key facts

| Fact | Value |
|---|---|
| Source water temperature | 199°F (93°C) (USGS record; developed pools are often cooled) |
| pH | 6.1 (Slightly Acidic) |
| Total dissolved solids | 88 mg/L |
| Elevation | 6,932 ft |
| Access | Roadside · Public Land, 180 ft from the nearest road (Lassen Peak Highway) |
| Land | Lassen Volcanic National Park, National Park Service |
| County | Plumas County |
| Nearest town | Chester |
| Coordinates | 40.44700, -121.53600 |
| Best months to soak | December, January, February (largest gap between water and average air temperature) |
| Nearest campground | MANZANITA LAKE GROUP CAMPGROUND, 5.8 mi |

## Soaking safety

**Very Hot Source, Use Extreme Caution.** At 199°F, the source water at Sulphur Works, Tophet Hot Springs 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.

## About Sulphur Works, Tophet Hot Springs

Sulphur Works, also on record as Tophet Hot Springs, is a roadside thermal area inside Lassen Volcanic National Park, Plumas County, about nineteen miles from Chester. The water is near boiling, 199 degrees in the record. It will scald on contact. Nobody soaks here. It is a place you stand back from and watch, on National Park Service land with open access.

Lassen Peak Highway runs within two hundred feet. Close to seven thousand feet up, and the snow numbers are enormous: more than seventeen feet in an average winter, on forty-six inches of precipitation. Averaged across the year the thermometer sits in the mid forties.

The site goes by two names on file, Sulphur Works and Tophet Hot Springs. It lies within Lassen Volcanic National Park, and the U.S. Geological Survey sampled the water in June 1981.

The record names midwinter as the best season, which sits oddly against seventeen feet of snow; check road status with the park. Manzanita Lake Group Campground is about six miles off. Do not approach the water; it is hot enough to cause severe burns in an instant. The USGS sample is from 1981 and reads slightly acidic.

## Water chemistry

Lab sample from 1981-06-30 (Water Quality Portal).

| Measure | Value |
|---|---|
| pH | 6.1 |
| Total dissolved solids | 88 mg/L |
| Calcium | 13 mg/L |
| Magnesium | 1.5 mg/L |
| Sodium | 3.7 mg/L |
| Sulfate | 25 mg/L |
| Chloride | 0.4 mg/L |

## Nearby

- Nearest city page: [Hot springs near Chester](https://www.soakingsprings.com/hot-springs/near/california/chester), 7 mi away
- State page: [Hot springs in California](https://www.soakingsprings.com/hot-springs/california)
- [Mill Creek Springs, CA](https://www.soakingsprings.com/hot-springs/california/mill-creek-springs): 150°F source, pH 6.1, TDS 88 mg/L, Short Walk, near Shingletown, Shasta County
- [Bumpass Hell, CA](https://www.soakingsprings.com/hot-springs/california/bumpass-hell): 199°F source, pH 6.9, TDS 42 mg/L, Short Walk, near Chester, Plumas County
- [Growler Hot Spring, CA](https://www.soakingsprings.com/hot-springs/california/growler-hot-spring): 203°F source, Short Walk, near Chester, Plumas County
- [Morgan Hot Spring, CA](https://www.soakingsprings.com/hot-springs/california/morgan-hot-spring): 205°F source, Short Walk, near Chester, Plumas County
- [Devils Kitchen, CA](https://www.soakingsprings.com/hot-springs/california/devils-kitchen-2): 203°F source, pH 6.7, TDS 49 mg/L, Hike, near Chester, Plumas County
- [Hot Springs Valley, CA](https://www.soakingsprings.com/hot-springs/california/hot-springs-valley): 83°F source, pH 6.7, TDS 49 mg/L, Short Walk, near Chester, Plumas County

## Questions

**What is the water temperature at Sulphur Works, Tophet Hot Springs?**
Sulphur Works, Tophet Hot Springs has a water temperature of 199°F (93°C). This is considered a hot spring, well above body temperature.

**Where is Sulphur Works, Tophet Hot Springs located?**
Sulphur Works, Tophet Hot Springs is located in Plumas County, California at 6,932 feet elevation, near Chester. Coordinates: 40.4470°N, 121.5360°W.

**How do I get to Sulphur Works, Tophet Hot Springs?**
Sulphur Works, Tophet Hot Springs has Roadside road access, with the nearest road being Lassen Peak Highway (180 ft from the road).

**Is Sulphur Works, Tophet Hot Springs free to visit?**
Sulphur Works, Tophet Hot Springs has Open access. It is managed by National Park Service.

**Can I camp near Sulphur Works, Tophet Hot Springs?**
Yes, Manzanita Lake Group Campground is located nearby (5.8 miles away).

**What minerals are in the water at Sulphur Works, Tophet Hot Springs?**
Water chemistry analysis shows the presence of pH, Total Dissolved Solids, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 6.1 (slightly acidic). Total dissolved solids measure 88 mg/L.

**Is it safe to soak at Sulphur Works, Tophet Hot Springs?**
No, not at the source. The water at Sulphur Works, Tophet Hot Springs reaches 199°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 thermal springs records, Water Quality Portal lab analyses, OpenStreetMap, Wikipedia/Wikidata, NOAA climate normals