About this spot
The Blue Hole is a bell-shaped, spring-fed pool along old Route 66 in Santa Rosa, roughly 80 feet in diameter at the surface and about 81 feet deep at its lowest known point, widening as it descends. Constant inflow of around 3,000 gallons per minute keeps the water near 62°F year-round and crystal clear, which is why it's one of the most popular inland scuba training sites in the country. Designated cliffs and platforms along the rim make this a legal, official cliff-jumping spot — stairs provide easy entry too — and it draws swimmers, snorkelers, and jumpers all season, getting especially crowded on summer weekends. Since 1976 a metal grate has sealed off the deeper cave passages to keep untrained divers out. Cold water and depth are the main things to respect here.