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Resort & lodgingClothing optional in some areas

Mercey Hot Springs

From $50
85–106°F
3 hr 2 min from San Francisco
Reservations required

An off-grid resort in the Little Panoche Valley, 13 miles west of I-5, where salty mineral water emerges at about 112F. Outdoor tubs run 102-106F and are clothing-optional and adults-only, while the heated swimming pool is 85-90F and needs swimsuits. Day use is by reservation from noon to 5pm, and stays range from cabins and Airstreams to RV and tent sites.

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✓ Verified November 2026

Photo: Mercey Hot Springs

Price: From $50
Water: 85–106°F
Nearest town: Firebaugh
From San Francisco: 3 hr 2 min
Reservations: Required

Plan your visit

Hours & season

Hours	Day use noon-5pm Office 9am-8pm Tubs 6-8am and 9am-midnight for overnight guests Pool 9am-9pm (11pm stated elsewhere)
Season	Open year-round Open 365 days, but the resort closed July 7-29 in 2026 Campfires only in cooler months

Tickets & booking

Price	Day use $50 per person plus fees, up to 5 hours between noon and 5pm Under 2 free Cabins from $195 Tent camping $75 Towels $2
Access	Reservation required
Booking	Day use must be reserved and prepaid by phone, (209) 826-3388 Not refundable, but can be moved to another date

Rules

Swimwear	Clothing optional in some areas Clothing-optional only in the outdoor hot tubs behind the cabins and the private indoor tubs Swimsuits only in the pool
Ages	Clothing-optional tub area is 18+ Under 12 must be with an adult at the pool and tubs
Dogs	No

On site

Lodging	Yes

Water temperature

60°F85–106°F125°F

Soaking-pool temperatures as published by the venue or land agency; they vary with season and flow.

Mineral profile

Total dissolved minerals

2,275 mg/L

Highly mineralized · Sodium–chloride (salty, brine-like water)

Tap waterMineral waterSeawater

Sodium741 mg/L

Calcium40.9 mg/L

Magnesium0.04 mg/L

Potassium5.7 mg/L

Chloride1,350 mg/L

Sulfate5.3 mg/L

Bicarbonate53.5 mg/L

Silica65.6 mg/L

pH: 8.9
Temp at source: 110°F
Lithium: 0.07 mg/L
Fluoride: 0.45 mg/L
Boron: 13.7 mg/L

Lab analysis of the source water at a USGS sampling site, sampled 2010 by the USGS and partners (data). Pool water may be cooled, mixed or treated, and spring chemistry is generally stable over decades. We report measurements only; we don't make health claims.

The pools

Pool	Temp	Setting
Therapeutic outdoor hot tubsBehind the cabins; clothing-optional, adults 18+, whisper-quiet. Closed 8-9am for cleaning.	102–106°F	Outdoor
Heated swimming poolMineral water, chlorinated; swimsuits only; no kids before 9am.	85–90°F	Outdoor
Private indoor tubsprivateSoaking rooms in the bath house; clothing-optional.	—	Indoor

As published by the venue. Temperatures shift with the seasons and the weather.

Facilities

WaterSome pools treated, some natural

Pool is chlorinated per Fresno County
Soaking tubs come straight from the source with no chemicals
Mostly sodium chloride

Showers: yes
Towel rental: yes
Restrooms: yes

Bring your own alcohol	Allowed
Glass containers	Not allowed
Smoking	Not allowed
Good to know	Alcohol allowed on site but not in tubs or pool No food, oils or glass in pool and tub areas Quiet zones No amplified music

What's here

off-grid, solar-powered resort
outdoor mineral hot tubs 102-106F
heated mineral swimming pool 85-90F
private indoor soaking rooms
cabins, Airstreams, tiny house, RV and tent sites
disc golf and labyrinth
dark skies for stargazing

Getting there

From San Francisco3 hr 2 min152 mi
From Fresno1 hr 47 min69 mi
From Fresno (FAT)1 hr 54 min73 mi

Typical driving time without traffic or snow.

Elevation	1,153 ft
Road	Paved road 13 miles west of I-5 exit 379 on Little Panoche Rd (J1) Do not use the Mercey Springs Road exit
Parking	Main lot north of the creek bed Overnight parking at cabins only next to Cabins #5 and #10

Things to do near Firebaugh

park

Little Panoche Reservoir Wildlife Area

State wildlife area on Little Panoche Creek along the road to Mercey.

park

Panoche Hills

BLM public land with open hills for hiking and wildflowers near Little Panoche Rd.

park

Tumey Hills

BLM recreation lands south of the Panoche Hills.

Nearby springs

Resort & lodgingSeasonalClothing opt.

Tassajara Zen Mountain Center

Carmel Valley, CA

A San Francisco Zen Center monastery at the end of a 14-mile dirt road in the Ventana Wilderness, with a historic stone bathhouse on the hot springs. The baths have indoor and outdoor plunges, steam rooms and a sauna; they are clothing-optional and separated by gender. Guests visit only in the summer season, from late April to early September, by reservation.

Overnight guestsView

Wild springTemporarily closed

Sykes Hot Springs

Big Sur, CA

Backcountry hot springs beside the Big Sur River in the Ventana Wilderness, reached on the Pine Ridge Trail from Big Sur Station. The Forest Service notes that several river crossings are required and can be impassable in winter high water. The trail and trailhead have been closed since August 2026 because of the Timber and Plaskett Fires.

FreeView

Resort & lodgingClothing opt.

Esalen Institute

Big Sur, CA

A retreat center on the Big Sur cliffs whose hot springs baths sit above the Pacific, fed by springs that emerge at about 119F. The baths have four communal stone tubs, individual claw-foot tubs and an upper-level tub with a lift, and they are clothing-optional. They are open only to overnight guests, and Esalen's public night-bathing reservations are currently closed.

Overnight guestsView

Tassajara Zen Mountain Center: 50 mi · Sykes Hot Springs: 56 mi · Esalen Institute: 59 mi

Sources (10)

· checked November 2026

Prices, hours and rules are checked against the official site and land-agency pages. Spot something out of date? Let us know.