Mermet Springs

Mermet Springs is a purpose built dive park that consistently delivers clear procedures, reliable fills, and organized shore facilities. It is the most complete quarry option within a day’s drive of Chicago for training, practice, and deep profiles. Use the notes below to navigate check in, fills, thermoclines, and where to stage gear efficiently.

• Best overall dive location in the Chicagoland regional area.
• Generally open from 9 am to 6 pm or 10 pm depending on the day (night dives are allowed).
• Significant, visible thermoclines. Around 40 ft expect a drop near 50 F or less. Very cold on the deep side below about 60 ft.
• Large, well managed fill station with Nitrox blending. Drop tanks, give your name, and staff track fills on a whiteboard. You settle up at the end of the day or weekend.
• Nitrox is partial pressure blended, not banked. Tanks must be O2 clean for Nitrox fills. Custom blends are available on request.
• Excellent suit up area with covered gazebos, individual picnic tables, mounted whiteboards, and bars for hanging exposure gear and rigs.
• Very large catfish patrol the quarry and are not shy.

• Strong training infrastructure supported by the gazebos and platforms.
• Large water area supports technical training and DPV dives.
• It gets dark below about 40 ft; bring a primary light.
• The 0 to 20 ft band can be murky during classes; maintain solid buddy awareness.
• Training platforms are installed down to 100 ft, making it ideal for deep practice.
• Dock entries have only small in water staging space, so conduct briefings on land or while floating.

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Step 1: Fill out the liability release form online before you arrive.
Step 2: Pull through the gate and cross the railroad tracks.
Step 3: Park in the first lot unless directed otherwise by staff.
Step 4: Go to the office, check in, pay the entry fee, and present your certification card.
Step 5: Go to your assigned diver gazebo. Groups can request a gazebo in advance.
Step 6: Suit up and dive.

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Dive Map as of Aug 2024

• Surface swim to the plane, descend, and you can tour most attractions on a single AL80 if you plan conservatively.
• Major items and platforms are connected with well marked lines and signs underwater.